The Big Slime is a 15‑centimeter‑tall aggressive slime that Mos encounters during her exploration. It is faster and more hostile than smaller slimes, attacking with tentacles and attempting to swallow its prey. It swallows Mos, nearly suffocating her, but she activates her Breath Holding talent and upgrades Claws to Claws II, allowing her to fight back. It demonstrates high regenerative abilities and poses a serious threat to Mos.