Tephraderm [Onslaught] Cat Beast Ugin's whispered summons led Sarkhan

Ugin's whispered summons led Sarkhan Vol to the moment that would echo down the centuries and seal Tarkir's fate: the primal battle between Ugin and Nicol Bolas

where X is the greatest amount of damage dealt by a source to a permanent or player this turn

All I found was you

that player plays with that card revealed in their hand and can't play it

Set: Battle for Zendikar Promos Type: Creature — Eldrazi Processor Rarity: Rare Cost: {5} When you cast this spell

Tephraderm [Onslaught] Cat Beast Ugin's whispered summons led SarkhanSet: Onslaught Type: Creature Beast Rarity: Rare Cost: {4}{R} Whenever a creature deals damage to Tephraderm, Tephraderm deals that much damage to that creature. Whenever a spell deals damage to Tephraderm, Tephraderm deals that much damage to that spell's controller.