The Throbbing Domain

Unlock the Throbbing Domain, Act 1's secret area. This requires a multi-step quest involving the house boss Guillotina. First, defeat Guillotina to obtain the Throbbing Gristle and place it at the end of the Caves. Then defeat her again for the Putrid Leach and take it to the Boneyard. Finally, defeat Guillotina a third time for her head, equip it on a cat, and run through the Caves or Boneyard to reach the Throbbing Domain. The cat carrying the head must be sacrificed to open the path.