Crystals are needed to win. You may have only one Crystal of each type in your collection. If you ever have one collected Crystal of each of the 8 types, you automatically win.
Each Crystal appears on two different Stomach cards. If you lose a Crystal, you may have a second chance to capture it.
Any time a Miner’s action needs to be downgraded but that is not possible, the Miner must choose a Crystal to lose instead.
If the Miner has no upgraded actions and no collected Crystals, there is no effect.
Example: The Beast just acquired an Attack Immune Response card that downgrades the Miner’s Stun action, but the Stun action is not upgraded. The Miner must now choose a tile to remove from their Collected Crystals area, regardless of whether the Capture or Eliminate actions are upgraded.