Source: hulkcollection.wordpress.com

9. Zzzax

Aside from being the last entry in every Comic Book Character Encyclopedia that will ever be published, Zzzax is also a lightning monster who likes to fight the Hulk.

After terrorists bombed a nuclear power plant, the electrical energy turned into a monster, which, as far as "bombing a nuclear power plant" goes, is actually one of the LEAST horrible things that could have happened. Zzzax stormed through the New York streets and threw Hawkeye into the East River before the Hulk caught up to him. Hulk was fairly useless (ya can't punch lightning), so Hawkeye took Zzzax down.

Eventually, Zzzax was merged with General Ross, and the lightning general went after the Hulk again. He did this over and over, only to be repeatedly defeated by wires and water like a Scooby-Doo ghost.

I know everyone seems to want General Ross to turn into Red Hulk in the MCU, but I say give me Zzzax any day.