Undermine lose 3 life counter target spell counterspell question magic

[Dude]

If other player casts a spell

and I have two undermines in my hand and enough mana to cast both of them

Can I cast both of them targeting the same spell and have him lose six life?

[Arix]

No. When the first resolves and counters the spell, that spell is removed from the stack. When the second tries to resolve, it sees that its only target (the spell it's trying to counter) is illegal, therefore Undermine itself is countered and none of its effects happen.