This ordinary bag, made from tattered, rotting cloth, appears empty. Reaching inside the bag, however, reveals the presence of a small, yucky object. The bag weighs 1/2 pound.
You can use an action to pull the yucky object from the bag and throw it up to 20 feet, including at a target. When the object lands or hits its target, it transforms into a swarm you determine by rolling a d10 and consulting the table below. See the Monster Manual for the swarm's statistics. If you hit a target with the swarm, the swarm acts as if it had successfully attacked the target. The swarm vanishes at the next dawn or when it is reduced to 0 hit points.
The swarm is friendly to you and your companions, and it acts on your turn. You can use a bonus action to command how the swarm moves and what action it takes on its next turn, or to give it general orders, such as to attack your enemies. In the absence of such orders, the creature acts in a fashion appropriate to its nature.
A swarm of frogs uses the Swarm of Insects stat block with the following changes: Substitute Climb speed of 20 with Swim speed of 20. Substitute Blindsight 10 with Darkvision 30. Add Amphibious trait (can breathe air and water) and Standing Leap: Can jump 10 feet horizontal or 5 feet vertical without a running start. The swarm of frogs has NO effective attack.
Once three yucky objects have been pulled from the bag, the bag can't be used again until the next dawn.
Vermin Swarms
D 10 Swarm
1 Swarm of Frogs
2 Swarm of Bats
3 Swarm of Insects (Beatles)
4 Swarm of Insects (Centipedes)
5 Swarm of Insects (Spiders)
6 Swarm of Insects (Wasps)
7 Swarm of Insects (normal)
8 Swarm of Poisonous Snakes
9 Swarm of Rats
10 Swarm of Ravens
Notes: Summoning, Utility
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