Sapper Tar

Cost: 50 gp

This viscous alchemical liquid softens earth and stone. As an action, you can smear the contents of this jar onto a nonmagical object or structure made of earth or stone, weakening up to a 1-foot cube of it for 1 minute. For the duration, the object or structure’s damage threshold is reduced by 5, and the weakened stone is pliable, becoming the consistency of firm clay. While the stone is softened in this way, you can write symbols in the stone, pull shackles or door hinges free from a wall, soundlessly embed a piton, or similar.

Alternatively, you can use an action to pour the tar onto a construct or elemental made of earth or stone within 5 feet of you or throw it at such a creature within 20 feet of you, shattering the tar’s container on impact. In either case, make a ranged attack against the creature, treating the tar as an improvised weapon. On a hit, the structural integrity of the earthen or stone creature is weakened, reducing the creature’s Armor Class by 2 for 1 minute. At the end of each of its turns, the creature can make a DC 12 Constitution saving throw, ending the effect on itself on a success.