Elvish Guidance, Arbor Elf, and Umbral Mantle

Prerequisites

• Elvish Guidance on the battlefield
• Arbor Elf on the battlefield
• Umbral Mantle on the battlefield
• Umbral Mantle attached to Arbor Elf
• Elvish Guidance attached to a Forest you control
• Arbor Elf does not have summoning sickness
• You control at least three Elves

Steps

1. Activate Arbor Elf by tapping it, untapping the Forest that has Elvish Guidance attached
2. Activate the Forest by tapping it, adding
3. Elvish Guidance triggers, adding at least
4. Activate Arbor Elf by paying and untapping it, giving it +2/+2 until end of turn
5. Repeat

Results

• Infinite green mana
• Infinitely large Arbor Elf until end of turn