Bristly Bill, Spine Sower, and Devoted Druid

Prerequisites

• Bristly Bill, Spine Sower on the battlefield
• Devoted Druid on the battlefield
• Devoted Druid has five or more +1/+1 counters on it
• Devoted Druid does not have summoning sickness available

Steps

1. Activate Bristly Bill by paying , doubling the number of +1/+1 counters on each creature you control
2. Activate Devoted Druid's first ability by tapping it, adding
3. Activate Devoted Druid's second ability by putting a -1/-1 counter on it, untapping it
4. Repeat from step 2 four additional times
5. Repeat from step 1
6. If Devoted Druid has six or more +1/+1 counters when you begin the combo, it will also get infinite +1/+1 counters which can be removed for infinite green mana

Results

• Infinite +1/+1 counters on creatures you control
• Infinite green mana