Slippy is Lewis' Blue Slimeling pet that he got from Mars in the Minecraft series, MarsQuest. Lewis was exploring Mars, when he found a Blue Slimeling Egg. He hit it with his pickaxe until it hatched open. They forgot about Slippy for a while until they found him again on Mars in their following series, Hole Diggers.
- Some of Slippy's favorite foods are doors and flint & steels.
- Slippy has grown slightly bigger since they forgot about him.