This is Toxic! I was debating whether or not I wanted to include him in the canon; but I decided to anyway.

Toxic is a wyvern that was created/genetically engineered in the same facility that had run tests on Corra. He was created for entertainment purposes along with the other few of his kind. His bright green dragon breath explodes into a beautiful burst of light seconds after being released. He was a hit and loved the attention!
...Until it turned out that the chemicals it contained eroded human skin upon contact. He was reclaimed by the lab for the acidic chemicals to be neutralized; but nothing was ever done and he sat locked away for years.

Theme: https://www.youtube.com/watch?v=3gyvHFBa5B0