Swap au!

This is a swap au of pressure! (I keep switching fandoms). Experiment z-13:gray skin. Fins. Blue gills on neck. Tips of claws are black. Has a third arm under f(right arm. Third arm is bandaged with blood on it. angler lure hanging from head. Has expandable uniform on. Bottom half is sea snake body with a whale tail fin. Can only slither due to not having legs. Adult. Emotionally unstable. Hate, love Sebastian. Can't speak. "The saboteur". Bites people Sebastian solace:black hair. Kisses his mother and siblings (I think he has siblings). Was sent in to retrieve the crystal. Has air tank on back for when he has to go underwater in the blacksite. Has ear piercings. Doesn't remember much. Is kinda scared but doesn't show it (he got angler a bunch of times). Sometimes flash beacons the "saboteur" (idk if I spelled that right). He/him. Human.