rule 34 2021 alien alien franchise animal genitalia animal penis anthro anus ass ball size difference balls big balls big butt blue eyes cervid claws colored duo equine penis erection fur genitals horn king lips looking at another male mammal medial ring nude penis pregnant pregnant male purple penis royalty shadow sheath short tail signature simple background size difference smile spikes spots standing strips teeth white body white fur wolfarion xenomorph xenomorph king yellow body yellow fur 5451542