Mortuary + Megatog + Bolas's Citadel + Ornithopter

Mortuary

Megatog

Bolas's Citadel

Ornithopter

How it works

1. Activate Megatog by sacrificing Ornithopter
2. When Ornithopter dies, Mortuary triggers, putting Ornithopter from your graveyard onto the top of your library.
3. Resolve the Megatog ability.
4. Cast Ornithopter from the top of your library by paying 0 life.
5. Repeat.

This clever loop turns zero-cost artifacts into an infinite engine by leveraging Bolas's Citadel to cast spells straight from the top of your library using life instead of mana. When you activate Megatog to sacrifice Ornithopter, Mortuary immediately catches the dying thopter and places it right back onto the top of your library. Because Bolas's Citadel allows you to replay that very same Ornithopter for zero life, you can repeat this sacrifice-and-cast cycle endlessly to pump Megatog to astronomical proportions while racking up infinite death and sacrifice triggers.