The glossy, iridescent carapaces of the beetles in the swarm scatter and tint light in a dazzling exhibition of colors. In bright light, a creature within 30 feet that looks at the prismatic beetle swarm must make a successful DC 13 Wisdom saving throw or be blinded until the end of its next turn. If the saving throw fails by 5 or more, the target is also knocked unconscious. Unless it’s surprised, a creature can avoid the saving throw by choosing to avert its eyes at the start of its turn. A creature that averts its eyes can’t see the swarm until the start of its next turn, when it can choose to avert its eyes again. If the creature looks at the swarm in the meantime, it must immediately make the saving throw. The saving throw is made with advantage if the swarm of prismatic beetles is in dim light, and this ability has no effect if the swarm is in darkness.

The swarm can occupy another creature’s space and vice versa, and the swarm can move through any opening large enough for a Tiny insect. The swarm can’t regain hit points or gain temporary hit points.