SFS Standard Gooey Engulf [two-actions] Feat 1

Frequency once per round

You can Stride and move through spaces of any creatures in your path. Any creature your size or smaller whose space you move through can attempt a Reflex save against your Athletics DC to avoid being engulfed. A creature unable to act automatically critically fails this save. If a creature succeeds at its save, it can choose to either be pushed aside or pushed in front of you at the end of your movement. You can only attempt to Gooey Engulf the same creature once per turn. You can contain as many creatures as can fit in your space.
A creature that fails its save is pulled into your body. It is grabbed and slowed 1, and it must hold its breath or start suffocating. The creature takes 1d6 acid damage at the end of each of its turns while engulfed (this damage can be improved by hardlight handwraps as though it were an unarmed attack). An engulfed creature can get free by Escaping against your Athletics DC. An engulfed creature can attack you but only with an unarmed attack or weapons of light Bulk or less. You're off-guard against these attacks. If you take piercing or slashing damage equaling or xceeding one fourth of your remaining Hit Points from a single attack or spell, the engulfed creature cuts itself free. A creature that gets free by either method can immediately breathe and exits your space. If you fall asleep, are knocked unconscious, or die, all creatures you've engulfed are automatically released.