Pinning Stomp

[John Wells 152]

Just bought Bestiary 4. I like the Colossus creatures, but found a small problem with them. Their Pinning Stomp ability is covered neither in their description nor in the Universal Monster abilities section. Has this been covered elsewhere?

[PoisonToast]

I can't find the ability listed in the PRD or d20PFSRD. I'm looking at my book right now.

Edit: pg 305

Pinning Stomp (Ex):

When a colossus is in its normal
form, as a swift action it can make a single melee attack
at its highest base attack against a target three or more
size categories smaller than the colossus. This attack
deals an amount of damage equal to twice that of its
slam attack plus 1-1/2 times the colossus’s Strength
bonus. If the colossus hits with this attack, it can
attempt a grapple check as a free action. This grapple
doesn’t provoke attacks of opportunity. If the grapple is
successful, the target is pinned and takes an amount of
damage equal to that of the colossus’s slam attack each
round at the start of the colossus’s turn until either the
pinned creature frees itself or the colossus moves out
of the pinned creature’s space. The colossus doesn’t
need to attempt grapple checks to continue the pin, nor
can it attempt a check to move, further damage, or tie
up the grappled creature. A colossus can at most two
creatures pinned with this attack at one time.