Thran Dynamo, Umbral Mantle, and Xenic Poltergeist

Prerequisites

• Thran Dynamo on the battlefield
• Umbral Mantle on the battlefield
• Xenic Poltergeist on the battlefield
• Thran Dynamo and Xenic Poltergeist does not have summoning sickness

Steps

1. Activate Xenic Poltergeist by tapping it, targeting Thran Dynamo
2. Activate Umbral Mantle's equip ability by paying , attaching it to the Thran Dynamo
3. Activate Thran Dynamo by tapping it, adding
4. Activate Umbral Mantle by paying and untapping it, giving itself +2/+2 until end of turn
5. Repeat

Results

• Infinitely large Thran Dynamo until end of turn