At its best, Star Trek is a science fiction series about humanity's ability to expand its horizons and overcome differences. But all that would be pretty boring without some great villains to overcome. Trek's bad guys have been a mixed bag, ranging from the laughable — looking at you, Harry Mudd — to the legitimately terrifying — The Borg.
Who's the baddest of the bad? Here's TIME's ranking of the 10 best Star Trek villains ever.