Obeka, Splitter of Seconds + Descent into Avernus

Steps

1. Deal combat damage using Obeka, triggering its ability, causing you to get that many additional upkeep steps after this one.
2. Move to your first upkeep step.
3. At the beginning of that step, Descent into Avernus triggers, putting two descent counters on it, then causing each player to create a Treasure token for each descent counter on it, and then dealing 1 damage to each player for each descent counter on it.
4. Repeat steps 2 and 3 for all remaining triggers.