>>54574333>There is literally no reason for serperior to be a dragon typeIt's a basilisk, which you yourself mention later on.
>>Grass/Ground >it's a burrowing snakeSerperior is never said to burrow in its Pokédex entries, has never been depicted burrowing in any official media, and it can't even learn any ground type moves in its debut generation. The snake it's based on (vine snakes) don't burrow either, they're strictly arboreal.
>>Grass/Dark >it's a basilisk a very mean creatureSerperior is never mentioned as being evil, mischievous or a trickster. Being a basilisk works better as justification for it being a dragon type, since one of the main themes of the Dragon type is powerful mythical creatures (especially reptilian ones).