1995: “Gack,” said Judith. “I don’t remember that. I wish you hadn’t. —Mary Daheim, Major Vices
1999: Sports was immediately consigned to a recycle pile where it was handy in case she heard the unmistakable gack-gack-gack machine-gun regurgitation sound of Midnight Louie about to deposit a hairball on some particularly cherished piece of paper or furniture. —Carole Nelson Douglas, Cat in an Indigo Mood
2000: He rubbed his throat, gacked like a cat spitting up a hair ball. —Dennis Lehane, Prayers for Rain
2002: I watch him to see if it’s just a furball or something worse, and I have to rush him to the hospital, but it turns out to be a furball. “Gack. Gack. Gack.” (Their furball-throwing-up noise.) —Stacy Horn, Waiting for My Cats to Die
2003: As I am laying concrete blocks to fix the foundation, I hear “gack gack gack” from the forest, getting closer. Then a large pileated woodpecker buzzes me twice before settling on the elderberry bush, [...] gacking at me sometimes to let me know he is very alert; [...] And he gacks and watches back out of one eye. —Marcus E Ryan, Two Diaries.
2004: I practiced faithfully every day, drawing my bow as she instructed, making my violin go Gack! Gack! like a cat coughing up a hairball. —Evelina Chao, Yeh Yeh's House