Quillspike, Phyrexian Altar, and Rendclaw Trow

Prerequisites

• Quillspike on the battlefield
• Phyrexian Altar on the battlefield
• Rendclaw Trow on the battlefield
• Rendclaw Trow does not have a -1/-1 counter on it

Steps

1. Activate Phyrexian Altar by sacrificing Rendclaw Trow, adding
2. When Rendclaw Trow dies, its persist ability triggers, returning it to the battlefield from your graveyard with a -1/-1 counter on it
3. Activate Quillspike by paying and removing the -1/-1 counter from Rendclaw Trow, giving Quillspike +3/+3 until end of turn
4. Repeat

Results

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