Fierce Beast

Fierce Beast
Your beast partner is especially large and strong, thanks to the care you’ve lavished upon it.
Prerequsites: Beast Handler
Benefit: Your beast partner advances, gaining 2 additional levels of Beast. No matter how many HD the beast gets in this manner, it cannot grow larger than one size category larger than its original size.
Normal:
Special: If your original beast partner is slain, you may apply the benefit of this feat to a new beast companion. You may select this feat multiple times; its effects stack.