Grinsplitter Weapon

Weapon (any slashing), uncommon

When you roll a 20 on your attack roll using this magic weapon, the target must make a DC 13 Wisdom saving throw or burst into laughter if it is a creature with an Intelligence score of 4 or higher. On a failure, the target falls prone, becoming incapacitated and unable to stand up. The target can repeat the saving throw at the end of each of its turns and each time it takes damage, ending the effect on itself on a success.