Além dos pontos mais filosóficos levantados por outros, há strongs evidências de que o bicho papão de Harry continua sendo um dementador após as lições de Lupin em Cálice de Fogo. Quando Harry está no labirinto, ele encontra um bicho papão e ele assume a forma de um dementador:
Then, as he turned a corner, he saw... a dementor gliding toward him. Twelve feet tall, its face hidden by its hood, its rotting, scabbed hands outstretched, it advanced, sensing its way blindly toward him. Harry could hear its rattling breath; he felt clammy coldness stealing over him, but knew what he had to do... ...A silver stag erupted from the end of Harry’s wand and galloped toward the dementor, which fell back and tripped over the hem of its robes... Harry had never seen a dementor stumble. “Hang on!” he shouted, advancing in the wake of his silver Patronus, “You’re a boggart! Riddikulus!” There was a loud crack, and the shape-shifter exploded in a wisp of smoke.
-- Harry Potter and the Goblet of Fire, page 622, US edition