You summon a swarm of poisonous frogs, which attacks all other creatures within its area. This swarm has the statistics of a centipede swarm, except it has the animal type and its poison deals Constitution damage instead of Dexterity damage. You may summon the swarm so that it shares the area of other creatures. If no living creatures are within its area, the swarm attacks or pursues the nearest creature as best it can. The caster has no control over its target or direction of travel.