Boom bug

The Boom bug is a throwing weapon in Fallout Tactics.

They explode in a buggy, toxic mist that damages all targets within a 5 hex radius.

Mutant ladybugs that have a tendency to explode. Boom bugs are pretty much considerably worthless compared to frag grenades, but there aren't a lot of grenades in the early stages of the game. Boom bug explosions can poison targets.

Locations
They can be found in large quantities (100+) on the dead bodies of the tribals at Peoria, where your mission entails retrieving 3 fusion batteries.

Beastlords almost always carry a few boom bugs with them in their war parties. This is on account of their use of animals and other nature-oriented weapons in combat.