Deathbloom Ritualist, and Umbral Mantle

Prerequisites

• Deathbloom Ritualist on the battlefield
• Umbral Mantle on the battlefield
• Umbral Mantle attached to Deathbloom Ritualist
• Deathbloom Ritualist does not have summoning sickness
• You have at least four creature cards in your graveyard

Steps

1. Activate Deathbloom Ritualist by tapping it, adding at least four mana of any color
2. Activate Deathbloom Ritualist by paying and untapping it, giving it +2/+2 until end of turn
3. Repeat

Results

• Infinite colored mana
• Infinitely large Deathbloom Ritualist until end of turn