The next 2 Chests you open contain 2 Relics. (Excludes boss chests)
The relic added to the chest by Matryoshka has a 75% chance of being a Common Relic, and a 25% change of being an Uncommon Relic.
This relic does not spawn beyond floor 40, excluding Endless mode.
Matryoshka is an Uncommon Relic.