Xanathar, Guild Kingpin

Mythic
Blue
Black
Promo

Mana value: 6
Power: 5
Toughness: 6

Legendary Creature — Beholder

At the beginning of your upkeep, choose target opponent. Until end of turn, that player can't cast spells, you may look at the top card of their library any time, you may play the top card of their library, and you may spend mana as though it were mana of any color to cast spells this way.

Set: Magic Online Promos (PRM)
Collector number: 92788
Released: Jun 24, 2002
Rarity: Mythic
Artist: Kieran Yanner
Color identity: Blue, Black
Layout: Normal
Commander: Can be your commander