Siege Modification (AER) from Aether Revolt, available at 401 Games Canada.

• Rarity: Uncommon
• Finish: Normal
• Artist: Sung Choi
• Card Text:
  Enchant creature or Vehicle
  As long as enchanted permanent is a Vehicle, it's a creature in addition to its other types.
  Enchanted creature gets +3/+0 and has first strike.