Card again sweater

[Malkavman]

From The rules:

Prevent
Applies to damage only. Prevent an amount of damage as specified by an ability. If less damage is dealt/taken than the amount being prevented, prevent all damage dealt/taken (in this case, only the amount of damage that was dealt/taken is prevented). Damage prevention is an interrupt.

Since the card-Again Sweater has no Maximum number of discards allowed once the card is zapped, the play should be legal.

(This means I can totally discard 13 cards to prevent 6 damage from a Toll Dragon, Matt) (hehe)