Yeah...see...I was playing with my powers and I discovered I could do this...
*hand starts glowing green and a greenish slime like substance oozes out*
I couldn't figure out what it was for. it didn't seem to really be of any use for an attack. So anyway, some got on a stain on my rug from where Spike peed before I litterbox trained him...yes...you can train dogs to use a litterbox...and it just vanished.
Turns out this stuff is great for removing stains, dirt, and other unpleasant things. So I went to the basement to try to clean some of the mold down there...I didn't actually bother cleaning up the slime cause I didn't think much of it...
...I think the rats must have started eating it or something.
For all we know these things could also have ghost powers...