ShortRiddles #6 - Adventure turned wrong.

Rob was brave college student and had his own gang of friends who all likes adventurers.

Once Rob and his friends went on adventurous trip to a deep jungle.

It was night and the whole gang wanted to try something special.

Near by the forest there was a grave yard and Rob came up with an idea.

He said "If any one of us can spend the whole night in the grave yard would be considered as the brave one".

No one wanted to take the risk but the brave Rob wanted to prove himself as the best.

Rob decides to spend the entire night an one there and left from their.

Next day when Rob's friends went to pick him up he found dead beside the tomb.

How did Rob die? Why was he found beside tomb?

Comment your answers down.