this is what i'll consider another section of elementary! you have now entered Lord Nobunga's palace and witnessing his horrible actions (giving people food poisoning, sending you to the slop pit). dont talk to nobunga when you meet him because, no matter if you say yes or no, he will probably kill you. also this location has probably my favorite sequence in the whole game (this guy vvvv)
this location also has another softlock, by going up the stairs and entering the farthest door on the left you'll encounter a brainfucker requesting to borrow your brain for a moment. saying no just makes them attack you, saying yes puts you in a scene where swampy's corpse has been pushed to the corner and their brain contained in a small jar, the "menu" button seeming completely gone and unable to even go back to the title screen (you're still able to, though! the button is just invisible, but can be clicked). also the altar can be found by continuing forward into Lord Nobunga's palace. in there, the altar is the second room on the left.