Leprechaun 4

On a distant planet, a power hungry Leprechaun kidnaps a Dominian princess, Princess Zarina, and plans to make himself king, but not if a bumbling brigade of space marines have anything to say about it. Their commander is a mad scientist by the name of Dr. Mittenhand, who\'s half machine thanks to one of his \"experiments\". Once on the planet, Leprechaun is blown up, but quickly is reborn through one of the marines (ala Alien) and wreaks havoc aboard the ship, meanwhile Dr. Mittenhand plans to use the princess for his experiments to make himself whole again. But now, after many of the marines are killed, Leprechaun turns Dr. Mittenhand into a grotesque monster and plans to blow up the ship. The remaining marines have to stop his evil plans and blow *him* up.

http://www.imdb.com/title/tt0116861/