Rite of the Shaded Serpent

Create an X/X legendary black Shaded Serpent creature token with Loom. (Creatures with Loom cannot be blocked by creatures with lower power.)
If X is greater than 5, also create X 1/1 black Shadow Whelp creature tokens with Flying and Possess. (Whenever a creature with Possess attacks, you may remove it from combat. If you do, attach it to target creature defending player controls and it becomes an Aura Enchantment with "Enchanted creature gets -1/-1." It becomes a creature again when the enc