Sky Worm

Boss that appears only in Floating Island portals. It will always appear over Air tiles. It has high HP and strength, but has no ranged attacks. It also start combat with a 1-turn vunerability penalty and 2-turn strength buff. Its main gimmick is its Devour special ability, which allows to insta-kill units and heal half its HP if it attacks and has 1AP remaining. Needless to say you will want to make sure none of your units are standing right beside or in a straight line from it when your turn ends. Defeating it will give you a FlightPotion with 2 uses, that changes any units movement type to Flying.