Even though Tom thinks this whole cake thing is a bad idea, he goes through with it anyway.
On the first night, nothing happens. But after dropping the second cake down the hole, Tom notices something: the bars that criss-cross the top of the hole have been bent.
Fearing that the cakes are making Mother Malkin stronger, Tom decides to give the last cake back to Alice.
Tom asks the lads in town where Alice lives, and they point him to Bony Lizzie's cabin. Oh, they also mention that a ton of babies have gone missing recently. Hm. Could it be that all these missing babies have something to do with Mother Malkin?
Alice meets Tom outside Bony Lizzie's cabin, and Tom gets mad at her for tricking him.
She tells him that Bony Lizzie made her do it. Not only that, but she tricked Old Gregory too. That witch business the Spook mentioned is a trap. "By now he's probably already dead" (8.70), Alice says.
Tom stomps away and chucks the basket of cakes into the river.
Knowing he has to stop Mother Malkin somehow, he asks the kitchen boggart to unlock the library. He says he'll give him every Sunday off. It works.
In the books, Tom finds an entry on Mother Malkin, who eats babies and has a giant scary son with tusks who they call Tusk.
Tom wonders if the cakes Alice gave him, which were all gooey and meaty, could have been made from the missing children. That's right: he could have been carrying around babycakes.
Tom realizes that Mother Malkin was buried alive because the Spook "believe it was too dangerous to kill her: once slain, she had the power to return and would be even stronger and more dangerous than before" (8.101). Who knew a few babycakes would cause so much trouble?