{T}, Collect evidence 3: Add one mana of any color. Put an unlock counter on Cryptex. Sacrifice Cryptex: Surveil 3, then draw three cards. Activate only if Cryptex has five or more unlock counters on it.
2024-02-02
Cryptex's first ability is a mana ability. It doesn't use the stack and can't be responded to.
2024-02-02
If you can't exile enough cards to meet or exceed the required mana value, you can't choose to collect evidence at all.
2024-02-02
Once you've announced that you're casting a spell, players can't take actions until you've finished doing so. Notably, opponents can't try to remove cards from your graveyard to stop you from collecting evidence.