Goblin Chieftain [Jumpstart] Aether Revolt Promos Set: March of the Machine

Set: March of the Machine Type: Artifact — Equipment Rarity: Mythic Cost: {3} Equipped creature gets +2/+2 and has protection from blue and from black

Set: Secret Lair Drop Promos Type: Legendary Creature — Human Wizard Rarity: Rare Cost: {1}{W}{U}{B} Flying

or if it's just a special card for MagicCon Philadelphia

Sacrifice Crystal Vein: Add {C}{C}

" Witness Reports

Goblin Chieftain [Jumpstart] Aether Revolt Promos Set: March of the MachineSet: Jumpstart Type: Creature Goblin Rarity: Rare Cost: {1}{R}{R} Haste (This creature can attack and {T} as soon as it comes under your control.) Other Goblin creatures you control get +1 +1 and have haste. "It's time for the 'Smash, Smash' song!"