Well. The combo definitely ran. The glaze fused the bottom of the cup to the kiln shelf (see second photo for birdseye perspective of the bottomless cup). It ran this badly despite stopping the combo at most halfway down the cup (see last photo).

Would love to try this combo again because it was beautiful - but dangerous 😆 Next time would try less layers and higher application.

The hearts were Black Underglaze by Coyote under Clear by Coyote.