Accomplished Alchemist, and Umbral Mantle

Prerequisites

• Accomplished Alchemist on the battlefield
• Umbral Mantle on the battlefield
• Umbral Mantle attached to Accomplished Alchemist
• Accomplished Alchemist does not have summoning sickness
• You have gained at least four life this turn

Steps

1. Activate Accomplished Alchemist's second ability by tapping it, adding at least four mana of any color
2. Activate Accomplished Alchemist by paying and untapping it, giving itself +2/+2 until end of turn
3. Repeat

Results

• Infinite colored mana
• Infinitely large Accomplished Alchemist until end of turn