Mister Fantastic acts as the leader and father figure of the Fantastic Four, and although his cosmic ray powers are primarily stretching abilities, his presence on the team is heavily defined by his scientific acumen, as he is officially acknowledged as the smartest man in the Marvel Universe. This is particularly a point of tragedy in regards to his best friend, Ben Grimm, who he has constantly tried to turn back into his human form but typically remains a large, rocky creature called the Thing. He is the loving husband of Susan Storm, father of Franklin Richards and Valeria Richards, and mentor of his brother-in-law, Johnny Storm.