I figured it out. Once all the books fall over, the final book hits the board, catapulting the basketball into the items on the shelf in panel three. After those items fall over, who knows where the calamity will go from there?
It could also be cutting the middleman, especially if the middleman causes gastrointestinal problems for GLAAARG, causing the monster to ‘Cut one’, as in passing gas.
“GLAAARG to the front desk, please.”