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.