Back Ultimecia, Omnipotent Legendary Creature - Nightmare Warlock Menace (This creature can't be blocked except by two or more creatures.) Time Compression - When this creature transforms into Ultimecia, Omnipotent, take an extra turn after this one
With the overall, standard victory condition for winning a Pokemon game being to collect six Prize Cards, being able to get hold of half of them in one fell swoop is pretty spectacular
We few, we happy few, we band of brothers
Recurring cards from your graveyard every turn provides a lot of value in long games, but constructed rarely gives Muldrotha time to truly shine
Creatures like Aboleth Spawn, Archivist of Oghma, Hullbreacher or Solitude are your best friends, as you can decide to slam them in your opponent's turn, while you keep mana up to counter their eventual best plays
If you survive it though, your opponent also takes the same damage, which can be quite useful