Casper

a natural born medium, has always seen and heard spirits so clearly that it made it difficult for him to differentiate between them and the living for awhile, causing him to be teased for 'talking to himself' 

powers are the result of a nearly dying in the womb, causing his soul to disconnect from his body. this allows him to see the spirit world just as clearly as he sees the living world, the two appear superimposed over each other.

he's essentially possessing his own body, his spirit body and physical body can even act independent of each other, though each will feel a profound emptiness when apart that becomes unbearable for extended periods of time (a couple days at the longest) his bodies will only retain independent thought as long as they are apart, they sync together into one consciousness when reconnected. additionally each one can only see or interact with one world at a time when disconnected, the physical body cant see spirits on its own and the soul cant interact with the physical realm on its own.