Trigger

Trigger is Evan Ross' loyal Cocker Spaniel in the Goosebumps book "Monster Blood." He travels with Evan to his Great Aunt Kathryn's house, where he initially gets into trouble with her cat, Sarabeth. After Evan and his friend Andy find Monster Blood, Trigger eats some and grows to a chaotic size. Once the Monster Blood is defeated, Trigger returns to normal. He later appears in Evan's dream and again at the end of the story, showcasing his loyalty by chasing away bullies and protecting Evan.