The description from the RC is:
A manticore is a horrid monster with the body of a lion, leathery bat wings, a tail ridged with spikes, and the face of a man with large, sharp fangs. It usually lives in wild mountain ranges. The manticore has 24 tail spikes, and can shoot six each round even when flying (ranges 50/100/180). The creature regrows two spikes per day. Its favorite food is man.
Manticores frequently track humans, ambush-ing them with spike attacks when the human group stops to rest. Another tactic is to stalk its prey like a great cat, creeping up close on an unsuspecting victim. When that victim is alone, the manticore fires off a barrage of tail-spikes to bring the victim down. The manticore then eats the victim. Less frequently, a pack of manticores will stalk and attack a group of victims.
I think I'm going to up the damage to 1d6/1d6/2d6. Think there should be some poison on the spikes?