With its mana cost of seven, hefty Ward cost, and ample evasion, Sire of Seven Deaths very much resembles Koma from earlier
(It has their total power, total toughness, combined mana costs, all text boxes, names, art, and so on.) It Came from Planet Glurg copies exactly what was printed on the original creatures and nothing more (unless any of those creatures are copying something else or is a token
If you do, untap all creatures you control and after this phase, there is an additional combat phase
Because similar to a commander in EDH, you can always count on having it available without having to draw it, which is very powerful
Archetype of ImaginationArchetype of Imagination is another permanent that can be used in a similarly game-ending manner, effectively granting our entire board unblockable (unless opponents' creatures have reach)