The exploding cat appears to be a housecat that has somehow managed to survive in the underground lairs they prefer. However, if examined carefully, and in a completely nonthreatening way, (A 1 on a D6 results in success), they will be seen to secrete a clear fluid, which mixes with the clays they prefer to nest in.
The exploding cat may mate in the normal fashion, but also have an ability to reproduce through merging their blood, which will result in litters of 30-50 for each two adult cats, and 10-15 for juveniles. They are able to reproduce in this secondary fashion from birth. As such, it is advised that those seeking to exterminate group of these creatures take care to kill them separately.