Shared Trauma (CM2) from Commander Anthology Volume II, available at 401 Games Canada.

• Rarity: Rare
• Finish: Normal
• Artist: Clint Cearley
• Card Text:
  Join forces — Starting with you, each player may pay any amount of mana. Each player puts the top X cards of their library into their graveyard, where X is the total amount of mana paid this way.