Greataxe of Evil Grin

You gain a +1 bonus to Attack and Damage
Rolls made with this Magic Weapon.
When you score a critical hit on your attack
roll using this weapon the target must make
a DC 13 Wisdom saving throw if it has an
intelligence score above 3. On a failed save
it bursts into laughter, falls prone and
becomes incapacitated. The target can repeat
the saving throw at the end of each of its turns
and every time it takes damage to end the effect.