Explanation for Lenny's "I've done it" tattoo

Lenny is ostensibly suffering from a form of Anterograde amnesia, but as far as I'm aware this is never explicitly confirmed.

Whether you believe that Lenny is Sammy Jankins, whether Sammy Jenkins actually exists or whether Lenny has projected aspects of his personal history onto Sammy is irrelevant: the important thing to take away from Lenny's stories is that he is an unreliable narrator, and his perspective is untrustworthy.

What we can take from this is that Lenny's 'flashbacks' are distortions of his own personal history, and as such do not necessarily have to conform to the rules of narrative logic.

The memories he 'creates' are part of a coping mechanism he seems to have developed as a way of dealing with the trauma of Whatever really happened, between him and his wife.

As you identified, the 'impossible tattoo' is just that: impossible. It's part of his fantasy.

I think the "I'VE DONE IT" tattoo is an important plot point and maybe even the climax of the movie. Its appearance is a sign Lenny realizes -- if only for a moment, before his next memory lapse -- that he has found a way to get some vengeance and also end his run of murders.

Lenny has just written himself a note to get a tattoo of Teddy's license plate number. He does this to punish Teddy because Teddy has just confessed to using Lenny. Lenny knows he himself will soon forget the confession and everything else that just happened. So Lenny decides to sentence Teddy to death, by getting a tattoo of Teddy's license plate, which later will make forgetful-Lenny think Teddy is John G.

The image of the "I'VE DONE IT" tattoo depicts Lenny just after writing the note to himself about Teddy's license plate -- briefly savoring a moment of victory in the form of a quick day-dream where he is with his wife, laying in bed, a proclamation of victory freshly inked on his chest.

Immediately after the appearance of the image with the "I'VE DONE IT" tattoo, Lenny's memory resets. Lenny is sitting there, having forgotten everything that just happened in the previous 5 minutes or so -- but holding that fateful note about Teddy's license plate, which will indeed lead Lenny to eventually kill Teddy, giving him vengeance and presumably ending his string of murders.

See for yourself: watch the scene again.

23 Dec 2014 EDIT: As mentioned in Bajur's answer, there is a mid-movie scene where Natalie is touching a blank spot on Lenny's chest, right where the "I'VE DONE IT" tattoo would be, and asks "And what about here?" Lenny answers : "Maybe it's for when I find him." I think that dialogue shows Lenny was saving the spot on his chest for when he catches the man he is looking for -- confirming that the moment where he "sees" himself with the "I'VE DONE IT" tattoo in that spot is a moment when he knows he has accomplished his goal.

7 May 2017 update: confirmed by critic Andy Klein in an analysis for Salon.com:

The scene of him and his wife in bed, the triumphant tattoo on his breast, can’t be a flashback. We’ve seen already that he doesn’t have the tattoo, so he can’t have had it in the past. How can he remember lying in bed with his living wife, with the tattoo “John G. raped and killed my wife” visible on his chest? It has to be a fantasy, which would make sense in the context. He thinks he has just avenged her (or has just set in motion a plan to avenge her). He’s visualizing his own sense of satisfaction and peace.

We never see the "I've done it" tattoo before that scene. It's like a conflicted memory to me. I mean there is no time travel in the film and he doesn't have the tattoo in the present or previous flashbacks. So the new flashback with that tattoo seems to be an effect of Teddy's conversation with him, which might have made Leonard doubt his own life.

check out the 35:29 min of the film , while natalie was touching lenny's chest she asks : and what about here ? lenny answers : maybe its for when i find him

you can clearly see a somewhat of a strange volume in his chest , note that it is in the exact place of his "i've done it" tatto and thats also the place where hes pointing out in that picture teddy took of him when he killed the real john G...

not sure if its important of not but i find it strange that i never saw anyone speaking about this scene, go look at it in youtube or something , not sure if it will be at 35:29 min but its in that scene lenny shows a picture of dodd to natalie and he then steps into her house (in the film is just after the scene where he wakes up in her room , in the chronological order its after he solves the whole dodd problem) btw english is not my mother language so be patient about my grammar.

That's just a day dream. I think he has it on his chest because he just looked at the photo of him pointing to his chest and Teddy just told him they already killed the second attacker (which that truth is up in the air). He is enjoying the momentary victory, revenge, before he forgets all that he has learned, which happens as soon as he sees the tattoo parlor, hence looking at the note card.

As for the him not being Sammy Jankins, I would like to you pause your movie at 1:30:03. You will notice that Sammy is looking at the doctor that passes between the camera and himself, when the doctor clears the screen it is Lenny sitting in the chair at the mental institute for a split second before it cuts back to him on a phone. This scene is before any mention of him being Sammy by Teddy.

I'm so tired of people saying "he just gets it removed- simple as that"

Have you ever seen the result of a removed tattoo?? It's not pretty, and it can take dozens of sessions to remove a tat, and even then there is almost always residual scarring or discoloration.

We would definitely be able to tell if he had removed it.

The whole reason Nolan uses tattoos is their permanence.

I think the image of him with his wife is a fantasy- none of the tats are ever removed.

It seems to me that the "I've Done It"/Wife scene is a manifestation of one of the biggest themes of this movie. So big, that Nolan even has the protagonist spell it out for us himself.

Remember the scene where Lenny goes on a brief diatribe about how unreliable memory is? He says he only trusts facts, and cites the fallibility of eye-witness testimony and all that? It's not just interesting conversation, it's one of the central ideas this movie is meant to convey, and this scene highlights it. After Lenny kills Jimmy, he is confronted with Teddy's information that challenges his own understanding of himself, and challenges his memories and reliance on his "facts." He tumbles through what he knows, thinks he knows, doubts, and desires.. Nolan wants the audience to not only see Lenny do this, but he wants us to feel it too.. just like the movie was edited in that funny order so that the audience would "feel" Lenny's parceled sense of memory, we deliberately see a combination of information and misinformation in that climactic scene in order to "feel" Lenny's confusion at this point. We deliberately aren't supposed to know if that vision is real or imagined because that encourages us as viewers to question what about his memories are real or not, which was arguably the whole point of the film.

Personally, I find it fun to imagine the many possibilities. Interesting observation, another theme present in this film seems to be the notion that Lenny would rather live on as a deliberately ignorant hero, or at least a righteous vigilante, than choose to live on with complete knowledge, including the knowledge that he is a monster. He makes this choice when he burns the success photos and copies Teddy's license plate. this is a pretty cool theme and pops up again in Shutter Island, as per Leonardo DiCaprio's character's final words. It's from different director/writer, but still similar thematically.

Actually its possible to fit it into the timeline of the movie

His wife survives the initial accident but he gets separated from her. He goes on a quest to find the supposed killer and gets the tattoos we see throughout the movie

He kills the person and gets the I've done it tattoo. His wife finds him later and they live together again as seen briefly. He puts her in a coma with the insulin but he can't take what he's done so he gets the tatoo removed so he can get lost in his quest to find the murderer again

Teddy helps him kill the actual "2nd man" and he does in fact get his "I did it" tattoo before he od'd his wife on insulin (if this even happened since we know Teddy is not adverse to lying to Lenny). Maybe the tattoo is there when Natalie points to it. He's telling her he's going to kill the guy and she's saying "what about this?" but when he says maybe I'm saving it for after, because he doesn't WANT in to be there, she just shrugs it off as more craziness. It makes a lot of sense, because there are plenty of blank spots she could have pointed to so why that one, specifically? It doesn't make sense because I'm pretty sure the "John G raped and murdered my wife" tat is there when his wife is looking at the "I did it" tattoo... Thoughts?

I think there are 3 possible theories, considering the objective truths that Nolan presents us (specially in the end of the movie).

1st (Lennys theory) - His wife was raped and murdered by John G and the story that Lenny tells about Sammy is true.

2nd (Teddys theory) - His wife was raped and survived the accident. Lenny got his amnesia and his wife tested him with the insulin shots. Lenny kills her with the shots. Lenny and Sammy are the same person (proved by the Sammy/Lenny hospital scene).

3rd (Wife + I've done it tatoo)- Lenny always says that his last memory was of his wife dying but he never saw her dead... She could still be alive and for a brief period could have lived whit Lenny while he was in search of John G. She could have accepted his thirst for revenge as long as it would stop with the killing of John G. The "I've done it" tattoo would be a reminder to Lenny that his search was over and he could finally live with his wife peacefully (they were both relaxing in bed with lenny's body full of tattos, including the "I've done it" one) ...When she realized that Lenny would not stop, she left him. I know that he doesn't have the tatto any more but for the sake of this theory let's say that he removed it xD

The last one is a little far fetched but at least can explain the I've done it bed scene.

Now guys what I think is that if the tatto is a day dream, it means the he wanted to cover that spot when he found the guy who killed his wife, he does not tatto "I did it" cause he wants a motive to live, wich is to find john G. He tells Natalie he would like to cover that spot in his chest, but he only meets Natalie after he killed Jimmy Grants, so it means that he can remember some things, wich makes no sense cause he really forgets a lot of things. So it means it's not a desease, it's psychological, but he won't accept it, just like Sammy. So Sammy never existed, he's a creation of Lenny's mind to help him make another truth about his wife, in fact, Lenny really killed her with an overdose. The day dream explanation makes more sense cause he is with his eyes closed while the scene shows, besides, he couldn't have it removed without any scars. Also, we have to remember that Sammy didn't know about his condition, cause if the doctor told him, he would not remember 20 minutes after it happened, but Lenny knew about his condition, wich is a bit odd and justifies that his condition was really psychological. Besides, we never saw any doctor giving Lenny the diagnosis. I really would like to see your thoughts about it.

So I think you guys missed something, it's a HUGE part of the film. I don't have the exact time of the sequence, but basicly when he tells the story about Sammy i'm talking about the part where we see Sammy in an institution sitting alone in a room with people just passing by. Well in that scene when 1 of the random people passes in front of Sammy, the actor changes and we see Lenard sitting in that chair wandering around. From that fact, you can basicly say that he's the one that killed his wife, that Sammy is Lenard. I think the "I'VE DONE IT" tattoo is a reminder for us that he's the one who killed her. When we see this tattoo it's the end of the movie where Lenard questions himself and we just understand that he just want to be happy with his condition therefore making up facts that are just wrong. Lenard is an unreliable narrator so we, spectators, need to find someone reliable. The only other guy is Teddy which we don't want to trust because he keeps saying "Don't beleive his lies" but he's the REAL cop in the story, he's the stable guy and yes he's using him but it doesn't make him a liar.

Summary for those who don't wanna read the whole thing : 1. Lenard is in fact Sammy 2. We can trust Teddy (even though he's using him) 3. the "I'VE DONE IT" tattoo, I think, is here when he has a glimpse of "reality" and is there to make us understand that we only see Lenard's part of the story.

I haven't seen the film in a few years, but I don't recall any evidence in the film that Lenny's wife was actually dead, although we (and Lenny) are supposed to assume that she is dead.

To me, that final scene showed that his wife had been alive all along, and that she and Lenny periodically got back together again. It wasn't a daydream. Of course, Lenny would have no memory of their reunions and no evidence that she was alive (unless he wrote a note or took a polaroid). Having no knowledge that his wife is alive, he would still carry out revenge the killings, and maybe his wife was encouraging him to do so.

There was something else that led me to believe his wife was still alive, something about the book she read over and over again, but I can't remember the detail right now.