Replying to Gift card with paypal question?

to verify my paypal, this kid let me use a walmart type gift card that he had with a few dollars on it

no i want to buy something and only have like 2 dollars of paypal funds. Paypal is saying i can use those 2 dollars plus take money from this credit card. the only thing is, im pretty sure there is absolutely nothing left on the credit card.

what will happen (besides nuclear war) if use the empty gift card to buy something? Will i get hunted down? will that kid who card it is? will it stop me before it even completes?