Day of the Dragons enters the battlefield, triggering itself, exiling itself and all other creatures you control and creating a 5/5 Dragon creature token for each creature exiled.
When
Day of the Dragons leaves the battlefield, it triggers itself, causing you to sacrifice all Dragons you control and return
Day of the Dragons and the other exiled cards to the battlefield.
Repeat from step 2.
Note that this is a mandatory loop that will end the game in a draw unless you have a way to end it or to use it for a game-winning effect.
Results
Draw the game.
Infinite creature ETB.
Infinite creature LTB.
Metadata
Bracket tag
PowerfulBracket 3+
For strong decks in bracket 3+
1
2
3
4
5
1 · Exhibition5 · cEDH
Bracket tags are estimated from the cards and results of each combo, as a guideline rather than a strict classification.