Termite shot

Termite shot was a specific variety of mage shot that, when it collided upon impact, released a brown viscous syrup that was particularly damaging to wood. After the syrupy substance was exposed it would bubble over and immediately weaken and dissolve any wood with which it made contact. This damage could not be magically stopped except by the spell dispel magic.

Analogues
In the mid 14 century DR, certain mages attempted to develop a substance similar to termite shot that would work on the stone and ceramic spelljammers of the illithids and neogi. It was rumored that the blood of both umber hulks and purple worms were used in its development.