<P> Pony Head (voiced by Jenny Slate) is a floating unicorn head who is Star's best friend from Mewni . She is described as sassy, sarcastic, and mischievous . She does not get along with Marco and is sometimes jealous of him when he interacts with Star . Nefcy said that Pony Head originated from an early story of Star where the latter was a fourth - grader and was discouraged during her attempts to recover a stolen bike; an image of Pony Head appeared and told Star not to give up . </P> <P> Jackie Lynn Thomas (voiced by Grey Griffin) is a skateboarding classmate who has been Marco's crush since kindergarten . She and Marco start dating in the season 2 episode "Bon Bon the Birthday Clown", but ended their relationship in the season 3 episode "Sophomore Slump". </P> <P> Margaret Skullnick (voiced by Dee Dee Rescher) is Star and Marco's homeroom and math teacher at Echo Creek Academy . She is accidentally turned into a green troll by Star in the episode "Match Maker" and then retains her form for the remainder of the series . </P> <P> The sensei (voiced by Nick Swardson) at a strip mall karate dojo that Marco attends . In season 2, it is revealed that Sensei is his actual first name, but in the guidebook he also goes by Brantley . He learned his karate from instructional videos, and attains his red belt with Marco in the season 2 episode "Red Belt". </P>

Star vs the forces of evil list of characters