Danny is deaf in his left ear.
It's a product of his accident, only partial and barely noticeable other than the occasional ringing of the ear or sudden water-in-ear feeling. But Danny doesn't really notice or mind (but mostly doesn't notice) due to his heightened senses and the fact the previous effects barely happen.
It comes to a head though when, after a particularly rough fight (maybe Vortex changing atmospheric pressure or Vlad/his parents trying a new invention, possibility a rough hit, possible crossover bs, etc), the water-in-ear feeling came back. Danny wouldn't mind at first, thinking it'd just go away like it usually does.
But it doesn't.
I dunno what else to put here. Feel free to extend.















