Happy Tree Friends began as a Mondo Media web series in 1999 and became an early internet phenomenon through Flash animation sites. Its formula of adorable animal characters meeting absurdly graphic slapstick deaths made it a staple of shock humor. Clips and sounds from the show circulate on meme soundboards because that cute-to-gory whiplash is instantly recognizable. Creators still reach for it when they want a nostalgic early-web reference that signals a wholesome moment is about to go horribly wrong.