So in my last question, Dinosaur Damage Dilemma, I was talking about damage for an Ankylosaurus and I realised that while the dinosaur can stun, the DC would be different for an animal companion. It says it is Strength Based, but I did the maths and that didn't make sense.
So the question is, how is and Ankylosaurus's Stun DC calculated?
And that's a tip about all animal companions. Each companion have their own rules, which are mostly different from the bestiary entry for that same creature.
For the ankylosaurus, this is how the ability actually reads:
Stun (Ex)
The ankylosaurus’s tail can deliver a powerful, stunning blow. A creature struck by this attack must make a DC (10 + 1/2 HD + Str modifier) Fortitude save or be dazed for 1 round. If the strike is a critical hit and the target fails its save, it is instead stunned for 1d4 rounds.
