Venom

Information
The Venom can only be brought at a store, however it was only for a limited time during the time when the Batman came out. It's a tier 5 dragon with Symbiote as a skill.

Skill Description
Symbiote has a cooldown of 11 seconds. It deals 450 + 20 damage, while increasing dragon speed by 1.75x and dragon damage by 25% for 7 seconds.