A jerkzilla is a dinosaur that is a jerk. Also a jerkzilla is a backstabbing bitch from another country.
A person who cannot control their emotions and erupts into being a monstrous jerk while creating tension in moments that would otherwise be fun and calm.
The table was filled with laughing friends who were enjoying the evening until Ethan showed up drunk and started being a total jerkzilla to all the girls.