Haldir, Lórien Lieutenant, and Devoted Druid

Prerequisites

• Haldir, Lórien Lieutenant on the battlefield
• Devoted Druid on the battlefield
• undefined minus , where X is Devoted Druid's toughness minus one available

Steps

1. Activate Devoted Druid's first ability by tapping it, adding
2. If Devoted Druid has toughness 2 or greater, activate Devoted Druid's second ability by putting a -1/-1 counter on it, untapping it
3. Repeat steps 1 and 2 until Devoted Druid has toughness equal to 1
4. Activate Haldir by paying , giving Elves you control +1/+1 until end of turn for each +1/+1 counter on Haldir
5. If Devoted Druid is tapped, activate its second ability by putting a -1/-1 counter on it, untapping it
6. Repeat

Results

• Infinite green mana
• Infinitely large Elves you control until end of turn