I heard somewhere that a student of lewis carroll's created a poem called Ghengis Kahn or something to that effect. I heard that this was a weird peom as he was on opium, does anyone know who he is?

I believe you are referring to Samuel Taylor Coleridge's "Kubla Khan".

I don't know anything about his being a student of Carrol's, though - I suspect you may have got your wires crossed a bit there.