If the player picks Something Sensible for the final mission, Michael and Franklin will chase down Trevor and kill him. He gets doused in gasoline, when a fuel tank breaks open. He then gets shot by Franklin or Michael, (depending on how long you take to shoot with Franklin), which ignites the gas and causes Trevor to burn to death following an explosion.
Due to the violent and horrific way Trevor died, some players believe his ghost can be seen at his trailer in Sandy Shores, where his red eyes peer out the kitchen window. The haunting is said to occur exactly at 2AM for one second. So far there is little evidence to support this claim. It is also believed that if the player saw Trevor's Ghost, the player's character would instantly be caught on fire, in an ironic throwback to Trevor's death.
There has been no credible evidence as of yet, and very few reports of this ever happening. There also is no code in the game related to this, making this myth highly unlikely.