Spelljammer: Adventures in Space (p.54)
The clown casts one of the following spells, requiring no material components and using Charisma as the spellcasting ability:
Dying Burst. When the clown drops to 0 hit points, it pops like a balloon, releasing a splash of putrid, corrosive ichor. Each creature within 5 feet of the clown when it bursts must make a DC 12 Dexterity saving throw, taking 10 (3d6) acid damage on a failed save, or half as much damage on a successful one. Squeakers. The clown wears shoes that squeak when it walks. The squeaking can be heard out to a range of 30 feet. The squeaking is silenced while the clown’s Phantasmal Form is in effect.
Shock. Melee Spell Attack: +5 to hit, reach 5 ft., one target. Hit: 17 (4d6 + 3) lightning damage. Ray Gun. Ranged Spell Attack: +5 to hit, range 120 ft., one creature. Hit: 7 (2d6) psychic damage, and if the target is a Humanoid with an Intelligence score of 3 or higher, it must make a DC 12 Wisdom saving throw. On a failed save, the target perceives everything it sees or hears as hilariously funny and is incapacitated for 1 minute. The target can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.
Phantasmal Form (3/Day). The clown veils itself and everything it is wearing and carrying in an illusion that makes it look like some other creature of its size or smaller (such as a child) or an object small enough to fit in the clown’s space (such as a floating balloon). Maintaining this effect requires the clown’s concentration (as if concentrating on a spell), and the illusion fails to hold up to physical inspection. As an action, a creature that can see the clown’s illusory form can make a DC 15 Wisdom (Insight) check, piercing the illusion and discerning the clown’s true form on a success.