During damage calculation: You can make the battle damage that both players receive from that battle becomes 0, and if you do, you can send 1 Level 4 or lower Insect monster from your Deck to the GY, then, if the monster you sent was a Normal Monster, you can Special Summon any number of cards with the same name as that monster from your hand, Deck, and/or GY. If a monster you control is sent to the GY by an opponent’s card effect: You can Special Summon 1 Insect Normal Monster from your GY. You can only use each effect of "Giant Ballpark" only once per turn.