Artefact

, rassemblez des preuves 3 : Ajoutez un mana de la couleur de votre choix. Mettez un marqueur « déverrouillage » sur le Cryptex.
Sacrifiez le Cryptex : Surveillez 3, puis piochez trois cartes. N'activez que si le Cryptex a au moins cinq marqueurs « déverrouillage » sur lui.
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.
Cryptex's first ability is a mana ability. It doesn't use the stack and can't be responded to.
If you can't exile enough cards to meet or exceed the required mana value, you can't choose to collect evidence at all.