Used to describe a person with an extremely good ability to retain information.
Duder 1: "Dude don't you remember? You thought that girl was hot in 9th grade, but she had really hairy arms."
Duder 2: "What? Are you sure?"
Duder 1: "Yea dude, that's why you backed off."
Duder 2: "Shit you're right. Damn your elephant memory."