Acererak's Disassembly

You point your finger at 3 creatures within range, releasing beams of sickly energy at them. Those creatures must succeed a Constitution saving throw or become poisoned, which also causes it to gain 1 level of exhaustion. While poisoned this way, a target may repeat the saving throw at the beginning of their turns. Three successful saves end the poison, and each fail grants an additional point of exhaustion. At 6 levels of exhaustion, the target melts into a pool of unrecognizable liquid.