Assassin Den + Berta, Wise Extrapolator + Training Grounds + Zirda, the Dawnwaker

Mana needed: {U}

RGWU identity

Commander legal

The 4 combo pieces

• Assassin Den
• Berta, Wise Extrapolator
• Training Grounds
• Zirda, the Dawnwaker

How to execute it

1. Activate Assassin Den by paying {U} due to Training Grounds and Zirda, putting a +1/+1 counter on Berta.
2. Berta triggers, adding {U}.
3. Repeat.

What the combo produces

• Infinite +1/+1 counters on a creature