Mei releases a large amount of lava from her mouth, which spreads into a broad, thin sheet as it travels through the air. Since it is shot upwards in an arc so as to descend onto the targets from above, it prevents the intended individuals from jumping up to avoid the attack. A great deal of smoke is created afterwards by the effects of the lava, so should the targets still be alive, a follow-up attack can be conducted while their vision remains obscured.
The phrase "Melting Apparition" (溶怪, Yōkai) is a pun on the Japanese words "apparition/demon" (妖怪, yōkai) and "dissolution" (溶解, yōkai).
Despite being named in its original appearance in the manga, the anime has yet to call this technique by its name, despite having appeared twice.