Activate only during the declare blockers step
Krark wanted that thumb back
If you added white to your deck, you could do the same thing but with Ephemerate and get a third Thoughtseize for free at the start of your second turn
(6/6/2025) If the target creature card is an illegal target as Golbez, Crystal Collector's last ability tries to resolve, it won't resolve and none of its effects will happen
Its unlikely to make any real impact on Standard, however that doesnt mean its not powerful in the right deck, most likely in Commander
With this card as your commander, you get access to this board-clearing effect as often as you like, alongside the keyword trample, this card turns Miku into a walking bomb of destruction