Type Zero Magic Crusher’s” effect is an activated effect.
Spell Cards discarded for another purpose may not be used for the effect of “Type Zero Magic Crusher.”
Netrep Q&As:
Q: Can a player use the effect of “Type Zero Magic Crusher” during the opponent’s turn?
A: Yes they can activate the effect of “Type Zero Magic Crusher” during the opponent’s turn. Curtis Schultz, 01/31/2004