Slime blocks come from Minecraft, the sandbox game developed by Mojang and first released in 2011, with the block itself arriving in the game's 1.8 update in 2014. Made from slimeballs dropped by slimes, the block bounces entities that land on it, which made it a favourite for player-built trampolines, launchers and redstone contraptions. Clips of that bounce spread through Minecraft gameplay videos and short-form edits, where the short, recognisable squelch now works as shorthand for a springy landing even outside the game.