Gruz Mother

Behaviour and Tactics
When it dies, it spawns a swarm of 7-8 Gruzzers that must also be defeated before the player can leave the boss area.
 * Charge: Charges straight at The Knight
 * Zig-Zag Slam: Repeatedly slams herself between the floor and the ceiling

Location
Found in the Forgotten Crossroads, sleeping peacefully until disturbed.

Two are fought at once in the Colosseum of Fools, however, they do not spawn Gruzzers upon death.

Trivia
Матка Жужж Майка Грузер
 * Gruz Mother was the first mini boss revealed in a YouTube gameplay demonstration video in which it was referred to as "Empress Muzznik".