The slimes in the Super Mario Mash-Up Pack (https://minecraft.fandom.com/wiki/Mash-up_pack#Super_Mario_Edition) are based on thwomps. Thwomps are stony enemies first appearing in Super Mario Bros. 3. In 2D games, it does its smash cycle whenever Mario is near, but in 3D games they always do that cycle. I included all three sizes in this Papercraft. Also, don't bother that the top and bottom spikes don't have fold lines. I forgot them on the tiny one, and I don't want to have to redo the medium and huge ones.

"Slimes are bouncy, cube-shaped hostile mobs that spawn deep underground in particular chunks, or at night in swamp biomes." -https://minecraft.fandom.com/wiki/Slime