Thanos: I don’t even know who you are refers to a quote from the character in the title, uttered in Avengers: Endgame.
After the release of the film, screen captions of the scene were spread online on reaction image macros and GIFs, expressing disregard for someone.
Avengers: Endgame premiered in the United States on April 22nd, 2019.
One of the scenes involve Scarlet Witch confronting Thanos (played by Elizabeth Olsen and Josh Brolin respectively) saying he took everything from her.
Thanos then replies, “I don’t even know who you are”.
The meme format was already rampant on Reddit a few days after the film debuted.
It would remain popular on subs such as r/EngameSpoilers, r/thanosdidnothingwrong and r/dankmemes.
Videos featuring the scene would also be uploaded to YouTube, by several users, throughout 2019.