Snape Threatens to Test Neville's Potion on Trevor

At the end of the Potions lesson, Snape gathers the class around to test Neville's Shrinking Solution on Trevor. Much to everyone's relief, the potion works, and Trevor transforms into a tadpole. However, Snape takes five points from Gryffindor, blaming Hermione for helping Neville, leaving the Gryffindors frustrated by the unfair treatment.