Basilisx

Captain Basilisx (or simply Basilisx) is a fan-made antagonist from the Mario series. He is a genetically enhanced Koopatrol captain who works for Bowser. Basilisx first appears in the the flash series Super Mario Bros. Z, as an original character made by Alvin-Earthworm.

Mario and Sonic: Worlds in Danger
Basilisx appears as a major villain in Jmkrebs30's Flash series Mario and Sonic Worlds In Danger, alongside Mecha Sonic. He, along with his Captain and Dr. Eggman plan to bring the Mushroom World and Mobius together. It's confirmed that He and Mecha Sonic will fight Mario and Sonic aboard the Death Egg near the end of the series.