Squeeze
Source Player Core pg. 192
Skill
Acrobatics
You contort yourself to squeeze through a space so small you can barely fit through. This action is for exceptionally small spaces; many tight spaces are difficult terrain (page 415) that you can move through more quickly and without a check.
Critical SuccessYou squeeze through the tight space in 1 minute per 10 feet of squeezing.
SuccessYou squeeze through in 1 minute per 5 feet.
Critical FailureYou become stuck in the tight space. While you're stuck, you can spend 1 minute attempting another Acrobatics check at the same DC. Any result on that check other than a critical failure causes you to become unstuck.
Sample Squeeze Tasks
Trained space barely fitting your shoulders
Master space barely fitting your head