Requires breaking "enderbeads." Specifically, these beads must touch a character's thigh or be positioned using a second or third bead.
While there are no officially "verified" secret mobs in —meaning hidden creatures built into the game's code that require pistons to reveal—the phrase "Lovely Craft Piston Secret Mobs"
In essence, is a search for reliable, working redstone piston traps or altars that force-spawn hidden mobs in the Lovely Craft environment.