Mages' Contest [Invasion] Commander Whenever a creature dies

Whenever a creature dies

Set: Signature Spellbook: Jace Type: Instant Rarity: Rare Cost: {U} Search your library for an instant or sorcery card

Set: Aether Revolt Prerelease Promos Type: Artifact Creature — Construct Rarity: Rare Cost: {X}{X} Walking Ballista enters the battlefield with X +1/+1 counters on it

"And topples round the dreary west A looming bastion fringed with fire

Mages' Contest [Invasion] Commander Whenever a creature diesSet: Invasion Type: Instant Rarity: Rare Cost: {1}{R}{R} You and target spell's controller bid life. You start the bidding with a bid of 1. In turn order, each player may top the high bid. The bidding ends if the high bid stands. The high bidder loses life equal to the high bid. If you win the bidding, counter that spell.