Sand Shark

If blood is shed in the open desert, d6 Sand Sharks arrive in d4 rounds.
Chomp
Ultimate Damage
If Chomp does 6 or more damage, Target loses a limb.
Eat or be eaten. These predators can smell blood from miles away. They are always on the hunt, patrolling the desert ready to go into a feeding frenzy at the first scent of blood.
This monster can be a typical monster encounter or be implemented as a combat timer. The idea is that the players know whenever that are in combat in the open sands, sharks will appear after a target has taken its first hit.
Let me know any feedback if you have ideas on how to make it more interesting.
Thanks!