Rat King

Rat King is one of two mini-bosses encountered in The Sewers (alongside Flushmaster), a grotesque conglomerate of rats fused together into a single monstrous entity. With 130 HP across both regular and Champion variants, the Rat King's real threat is not his own body but the relentless swarm of minions he summons every turn. The creature references the real-world phenomenon of rat kings, where rats become tangled together by their tails, though notably in Mewgenics the rats grow out of the Rat King's body rather than being externally fused.

In Phase 1, the Rat King deals 5 damage and uses a Toss Attack that throws adjacent units (similar to the Tank ability), while spawning two Lil' Rats each turn that act independently. At half health, he transitions to Phase 2, gaining +1 Brace, +3 Damage Up, and +2 Speed, becoming significantly more aggressive. In Phase 2 he spawns Poops instead of Lil' Rats, and eventually upgrades to spawning Dips. The toss attack makes standing adjacent to him extremely risky, as he will hurl your cats across the arena for 5 damage on impact, disrupting formations and potentially throwing cats into hazards.

Board control is the key to this fight. AoE and bounce attacks are essential for clearing the rat flood while maintaining pressure on the King himself. The Thief class excels here, using teleport abilities to strike from behind and immediately reposition out of toss range. A recommended composition is Thief, Hunter, Tank, and Cleric, where the Tank absorbs the Rat King's direct hits while the Hunter and Thief deal damage from safe distances. Prioritize killing summons when they threaten to overwhelm your formation, but do not ignore the Rat King himself, as his Phase 2 buffs make the fight dramatically harder the longer it drags on.