Rainbow Pattern Spell
D&D Description of the Rainbow Pattern Spell : A glowing, rainbow-hued pattern of interweaving colors fascinates those within it. Rainbow pattern fascinates a maximum of 24 Hit Dice of creatures. Creatures with the fewest HD are affected first. Among creatures with equal HD, those who are closest to the spell's point of origin are affected first. An affected creature that fails its saves is fascinated by the pattern.
Deeper info on this Dungeons & Dragons Rainbow Pattern Spell