Combine Guildmage, and Bloodthrone Vampire

Prerequisites

• Combine Guildmage on the battlefield
• Bloodthrone Vampire on the battlefield
• available

Steps

1. Activate Combine Guildmage's first ability by paying and tapping it, causing your creatures that enter this turn to enter with a +1/+1 counter on them
2. Activate Bloodthrone Vampire by sacrificing the persist creature
3. When the persist creature dies, its persist ability triggers, returning it from your graveyard to the battlefield with a -1/-1 counter on it and at least one +1/+1 counter on it due to Combine Guildmage
4. Remove a -1/-1 counter and a +1/+1 counter from that creature as a state-based action
5. Resolve the Bloodthrone Vampire ability
6. Repeat from step 2

Results

• Infinite creature ETB
• Infinite creature LTB
• Infinite creature sacrifice triggers
• Infinite death triggers
• Infinitely large creature until end of turn