As the shark thing charged again, Dave twisted suddenly out of the way of the bulk of the jaw.  Rotating his hips, he quickly brought his legs up, kicking off the megalodon's gills and spinning himself around.  Partway through his rotation, he jabbed his knife into the creature and let its own charge drag his blade along its body, carving a deep gash a few feet in length.  Dave finished his rotation as the beast swam past, ending up in the same position he started in but facing the shark as it moved away.<br/><br/>[16 successes]