Phobia is a Teen Titans villain who has the power to make people live their fears.
Stephanie and Cassandra tried to save Harley Quinn from a team of Jokerized (infected with venom from The Joker, driving them insane) villains in Last Laugh #3. They included Carnivora, Dervish, Killer Frost and Phobia. Batgirl, Spoiler and Harley all got captured by the team. Fortunately, they got rescued by Power Girl.