Insect Swarm

A single velvet ant, grasshopper or locust is no threat, but swarms of them devastate crops and forests and can endanger every creature they meet. Swarms migrate, sleeping wherever night finds them. Each female produces as many as 100 eggs yearly, and there are no leaders, specialists or treasure. In either kind of swarm, each point of damage kills 1d20 insects. Fire or smoke disperses them and water washes them off, and once half a swarm is dead the rest scatter.

These look like plump ants coated in soft fuzz, usually red or black but sometimes yellow, orange or brown. A swarm devours everything, plant and animal alike. Its size is 1d100 x 1,000 ants at about 100 per square foot, so 10,000 fill a block roughly 10 feet on a side. Meeting an obstacle, it turns 90 degrees and keeps going. Each round a creature in contact has an 80% chance of being bitten for 1d4, and must save vs. poison or endure agonizing pain for 2d4 turns, suffering -2 to attack and damage rolls. Survivors try to hide as well as scatter. Destroying a swarm earns 975 XP. They eat grass, seeds and meat, carrion most of all, and their venom makes them inedible to predators.

Grasshoppers are about 2 inches long, green or brown, and leap some four feet. Locusts are a short-antennaed variety that chirp by rubbing hind legs against wings. Their swarms fly in straight lines between rich fields, so they are easy to sidestep. A grasshopper swarm numbers 1d100 x 10,000, and a locust swarm twice that, at about 20 per square foot (or per cubic foot in flight). Each round a creature inside has a 90% chance of a 1-point bite, and vision is limited to 2d4 feet. Wiping out a swarm earns 2,000 XP. They favor grain and seeds and are prey for snakes, mice, birds and spiders, and carnivores can safely eat them.