Tasha's Uncontrollable Hideous Laughter
3rd Level Magic-User spell
Range: 180 feet
Duration: 1 round per level
Area of Effect: 1 creature per 3 levels
The victim of this spell perceives everything as extremely funny. On the round the spell is cast, the target begins smiling, then giggling, and finally collapsing into gales of uncontrollable, hideous laughter. The target is entitled to a save vs. spells to avoid the effect, but if this is failed, no action is allowed during the first round.
The saving throw vs. spell is modified by the Intelligence of the target. Creatures with Intelligences of 4 or less (semi-intelligent) are totally unaffected. Those with Intelligences of 5-7 (low) save with -6 penalties. Those with Intelligences of 8-12 (average to very) save with -4 penalties. Those with Intelligences of 13-14 (high) save with -2 penalties. Those with Intelligences of 15 or greater (exceptional) have unmodified saving throws.
Although this magical mayhem lasts only a single round, the affected creature must spend the duration of the spell controlling the giggling fits and recovering, resulting in a penalty of -2 to all dice rolls made during this period. In addition spellcasters must make a check against their relevant ability score (Int for Mystics, Magic-Users and Elves, Wis for Clerics, at the aforementioned -2 penalty) before attempting to cast any spells. If this check is failed, the spell may not be cast, though other action may be taken instead, with only a -1 penalty to initiative. The spell is not lost, and may be attempted again later.
Magic Item use is not affected by this spell.
Note that we've tweaked this spell a bit from its function in AD&D, this is intended to fit it better into the spell selections for magic-users and elves in the BECMI D&D rules.