Alcazar

Alcazar is a male alien grasshopper who can change shape, was engaged to "five weirdos" at the same time, and tricked them into believing he was the ruler of Cyclopia.

Story
After discovering that Leela was the only one of her species, he morphed into a cyclops and told her they were the only ones left. Alcazar treated Leela like his servant and would have gotten married to her if Fry and Bender hadn't revealed he was planning to marry four other women, who would later take revenge on their groom by giving him a savage beating, after which he returned to his real form.

He later attended the ceremony for the implosion of the violet dwarf star in 3009 from the movie "Into the Wild Green Yonder".

Trivia

 * He's more than likely a parody of Al Bundy from Katey Sagal's former show "Married...with children."