Elemental Nivmagus

Exiling a spell is not the same as countering it, although the spell won’t resolve in both cases. You may exile a spell that can’t be countered.

You can exile a copy of an instant or sorcery spell to activate Nivmagus Elemental’s ability if you control the copy.

You exile an instant or sorcery spell you control from the stack, not an instant or sorcery card in any other zone.