Rot grubs are nearly mindless creatures that exist primarily in swarms, a stat block for which is provided in Volo’s Guide to Monsters. They’re a nasty surprise for any adventurer who stumbles across them, since the only way to fight them off once they’ve burrowed into you is to intentionally burn yourself. However, to talk about their having “tactics” is to give them too much credit, and I’m only bothering to write them up because a reader requested it.
A swarm of rot grubs is easy to hit, having an armor class of only 8, but not so easy to destroy. The swarm is resistant to piercing and slashing damage, reflecting the fact that you can kill a lot more grubs with a broad bashing weapon than with a thin cutting edge or poking point. The swarm is also immune to most debilitating conditions, stunned and unconscious being two standout exceptions. The swarm can be blinded, but that doesn’t mean much, since it has 10 feet of blindsight. Except for its Constitution, which is average, the swarm’s ability scores are pitifully low.
The swarm has only one attack, a bite that does only indirect damage. Rather than take place at the moment of attack, the damage occurs at the start of the target’s turn, and it varies in proportion to the number of grubs that have burrowed into the target’s flesh (1d4 per hit). The target must cauterize the bite wound on this turn, or the burrowing grubs will do continuous round-by-round damage until the target is either cured of the infestation or dead. (more…)