When a random person on the internet becomes a meme, the story usually ends one of two ways: they either fade back into obscurity with a weird bit of fame to their name or worse, they milkshake duck and their newfound fame leads to the discovery of their problematic past and subsequently ruins their life. Stefán Karl Stefánsson was the rare person behind the meme who was actually, it seems, perfect. After entering the internet's consciousness after his performance singing the song "We Are Number One" as the villainous Robbie Rotten in the children's show Lazy Town, Stefán Karl was exposed as… a pretty great guy. His newfound fame coincided with a cancer diagnosis that led to a tough two-year battle with the illness, which he ultimately succumbed to last week at the age of 43. Among celebrity deaths, this one particularly stung the meme community, who mourned Karl as they celebrated him in life: with memes. Here's how the community reacted.