Timothar, Baron of Bats, Breath of Fury, Pawn of Ulamog, and Mass Hysteria

Prerequisites

• Timothar, Baron of Bats on the battlefield
• Breath of Fury on the battlefield
• Pawn of Ulamog on the battlefield
• Mass Hysteria on the battlefield
• Breath of Fury attached to Pawn of Ulamog
• You control an additional nontoken Vampire
• An opponent cannot block creatures you control

Steps

1. Deal combat damage to an opponent using Pawn of Ulamog
2. Breath of Fury triggers, causing you to sacrifice Pawn of Ulamog, attach Breath of Fury to another nontoken Vampire you control, untap all creatures you control and get an additional combat phase after this one
3. Pawn of Ulamog dies, triggering itself and Timothar
4. Resolve the Pawn of Ulamog trigger, creating a 0/1 Eldrazi Spawn creature token
5. Activate the Eldrazi Spawn by sacrificing it, adding
6. Resolve the Timothar trigger, causing you to pay and exile Pawn of Ulamog to create a 1/1 Bat creature token
7. Move to your next combat phase, and deal combat damage to an opponent using the creature that has Breath of Fury attached, as well as the Bat token
8. The Bat and Breath of Fury trigger
9. Resolve the Bat's trigger, causing you to sacrifice it and return Pawn of Ulamog from exile to the battlefield tapped
10. Resolve the Breath of Fury trigger, causing you to sacrifice the creature it is attached to, attach Breath of Fury to Pawn of Ulamog, untap all creatures you control and get an additional combat phase after this one
11. The Vampire dies, triggering Pawn of Ulamog and Timothar
12. Resolve the Pawn of Ulamog trigger, creating a 0/1 Eldrazi Spawn creature token
13. Activate the Eldrazi Spawn by sacrificing it, adding
14. Resolve the Timothar trigger, causing you to pay and exile the Vampire to create a 1/1 Bat creature token
15. Move to your next combat phase, and deal combat damage to an opponent using Pawn of Ulamog and the Bat token
16. The Bat and Breath of Fury trigger
17. Resolve the Bat's trigger, causing you to sacrifice it and return the Vampire from exile to the battlefield tapped
18. Resolve the Breath of Fury trigger, causing you to sacrifice Pawn of Ulamog, attach Breath of Fury to another nontoken Vampire you control, untap all creatures you control and get an additional combat phase after this one
19. Repeat from step 3

Results

• Infinite combat damage
• Infinite combat phases
• Infinite death triggers
• Infinite ETB
• Infinite LTB
• Infinite mana creatures you control can produce
• Infinite sacrifice triggers
• Infinite untap of creatures you control