they could even (given an update to prop.js because that’s probably the only way you’d be able to set them besides console in such a case) have arrays, with if Array.isArray and .includes to check elements against them
Molten and magma pixels--and only molten and magma pixels-- move through, but internally, they immediately tryMove backwards in the same tick and up through the trapdoor, making them not having gone anywhere
But molten, magmoid things, regardless of whether they're from a mod--things like regular magma, molten amalgam, felsic magma, molten iridium, and molten steel--have this issue