Gronk is a member of Maelstrom's Minions which are a trio of superhumanly powerful agents that carry out Maelstrom's biddings. Gronk is believed to be either a human being or Deviant given power by Maelstrom through means of Terrigen Mist. Gronk and his other two companions, Phobius 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. Gronk has battled the Thing and Hercules in personal combat but eventually defeated. The current whereabouts of Gronk and Maelstrom's Minions are unknown.  

Creation

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

Powers and Abilities

Gronk has superhuman strength and can lift about 20 tons. He also has the ability to secrete a highly adhesive chemical from his pores, enabling him to adhere to virtually anything or make anything stick to him.  There is a limit to his stickiness, however.  For instance, Hercules was able to punch Gronk off of himself.