pf2e.fyi
From Pathfinder Lost Omens Ancestry Guide, which isn't enabled.

Slither

FEAT 1

You are an expert at moving through extremely tight spaces. You gain the Quick Squeeze skill feat, even if you're not trained in Acrobatics. When you roll a success on an Acrobatics check to Squeeze, you get a critical success instead.

Pathfinder Lost Omens Ancestry GuideOGL