Bender flushes Nibbler down the toilet, but the Professor fits him with a chip that makes him feel Leela’s emotions. So they head to the sewers to find Nibbler.
Nah, good guess but Bender flushes himself in that one and Leela and Fry go looking for him. I think this is Luck of the Fryish, when they went looking for Fry's seven-leaf clover.
Either way, he declares that his luck is changing right before the ladder he's climbing into the sewer has a bar break off, sending him plunging into either just the water or onto someone slimy
Edit: wait, it's definitely Luck of the Fryrish. They're heading to Old New York to find Fry's clover. Same deal, the ladder breaks after he declares no more bad luck