Stunt

From Wildermyth Wiki

A “critical hit” that produces different effects against different monsters

An example is being stunned.

Elemental Stunts

Fire

sends up to 3 fireballs at nearby enemies

Life

Grants two temporary health to the hero.

Stone

shreds 1 armor from all foes within 2 tiles of target

Water

gives a free action point, at most once per turn.