The eleven-mana creature has its casting cost reduced by X generic mana, with X equalling the combined toughness of all creatures you control, meaning you can drop this bad boy as early as turn three in some cases
These include (list updated as previewed): Brainstorm Crop Rotation Expedition Map Fatal Push Lightning Greaves Urza's Mine Urza's Power Plant Urza's Tower Additionally, we have clarified that VIP Edition contains either 2 foil borderless showcase cards with rare expansion symbols or 1 showcase rare and 1 showcase mythic, not 2 mythic rare showcase cards
As long as your deck runs heavy on draw and discard, you fill your graveyard up with expensive spells (or cheap ones simply by casting them), then once this big boy hits the battlefield, you can start reigning terror on your opponents by casting those big spells from beyond the grave for free
Id love to be wrong about Viven as she seems like a fine choice for the current grindy metagame (if companions dont run over the format)
Despite that, it has gone underplayed since it was printed in Duskmourn: House of Horror