Psyklop is member of a race of insectoids that worshipped "Dark Gods". At some point in history the Dark Gods cursed his people with sleep, but when they needed a new power source they awoke Psyklop and made a deal with him. If he could find their power source, they would revive his people.
Psyklop pursuits the Hulk because he believes him to be the only source of energy strong enough to satisfy the Dark Gods. In the time since his last encounter with The Hulk, Psyklop has transformed from one individual being into an entirely new species controlled by a deluded hive-mind that continues to serve the will of The Dark Gods that Psklop himself once served as an individual.