OB-1, Slot-Bot

Defender
Place Your Bets - {1}: Roll a 20-sided die. If 1-12,
OB-1's controller makes 1 Treasure. If 13-19, the roller makes 3 Treasures. Only an opponent may activate this ability.
Ding, Ding, Ding! - When a player rolls a max
roll, they create a Hit the Jackpot enchantment
token with "When you tap a land for mana, add
an additional {1} to your mana pool."