Phobius is a member of Maelstrom's Minions which are a trio of superhumanly powerful agents that carry out Maelstrom's biddings. Phobius is believed to be either a human being or Deviant given power by Maelstrom through means of Terrigen Mist. Phobius and his other two companions,  Gronk and Helio were first dispatched to Hydro-Base to steal the Anti-Terrigen Compound invented by Reed Richards and the Inhumans. They succeeded with their task but were eventually captured. Maelstrom sent his ally Deathurge to execute them. More clones of Maelstom's Minions were created and have battled the Thing, Inhumans and both the East and West Coast Avengers on seperate occasions. Phobius acts as the team's interrogator with the use of his special abilities. The whereabouts of Phobius and the rest of Maelstrom's Minions are currently unknown.  

Creation

Phobius was created by Ralph Macchio, Mark Gruenwald, Gene Day and Ron Wilson in 1981 and first appeared in Marvel Two-In-One # 71.

Phobius using his abilities to stimulate the fear centers of his enemies.

Powers and Abilities

Phobius can psionically stimulate the fear centers of the brain of other persons or animals, creating specific fears or phobias.  He is powerful enough to cause Captain Marvel to be caught in deep, almost overwhelming fear for a long period of time, which she was only able to overcome at great effort.  His power can cancel out Firefox's "pleasure" power.