2 Characters have a disease where their body makes them think they are actually being hurt (e.g. being electrocuted) this is in season 1 and 2.
In season 2 there is a flashback where a child has a seizure because he is scared, he is later shown to be ok
In season two Agrajag is killed (presumably) off-screen but is brought back to life as a puppy in the final episode.