Because Warumonzaemon and Ladydevimon were just far too vanilla for a children's series about pet monsters, the two apparently got incredibly wasted at an evil digimon BDSM orgy and conceived this self-mutilating gas-masked latex gimp-bear with needle and razor blade stuffing. It's supposedly a relatively timid creature who took on this appearance to "camouflage" itself amongst more evilDigimon, but I think the little guy is confusing "evil" with "hardcore kink." I just joke because it's easy, of course. Porcupamon is undeniably cool as hell to look at, hilariously tragic and just cartoonishly ghoulish enough to take the #3 spot.