Cleon
Legend
Yeah, there's precedent for that. Rend Fallen, as per the Abyssal Maw in MMII.
For once, overrunning looks like an appropriate ability. Only catch is that it'll still provoke an attack of opportunity against the elephant bird.
Oh I forgot Improved Overrun didn't negate the standard AoO. I'd rather give its beak the Trip special attack than have it risk opportunity attacks.