Spell Cake

The Spell Cake is a magical spell that takes the form of a small pastry. It has the ability to change one's fate if consumed. The Witch created the spell and gave one to Merida.

Brave
After Merida learned that the woman the Will O' the Wisps led her to is a witch she asked her to give her a spell; to change her mother so she doesn't have to marry one of the lords' sons. But the witch knew what might happen if she gave her one and the side-affect it would have if she had a fight with the one she wants to use it on or herself and tried to chase her out. But Merida told her that she'll trade her necklace for all of her bear carvings if she gave her the spell.

The witch agreed and used her magic to change her carving room into a conger room so she could make it. She told Merida that the last time she made such a spell was for a prince, so he could have the strength of men as he gave her his ring as payment. Merida wasn't sure why it took the form of a cake, but the witch told her that "it would do the trick".

After Merida returned the castle, she placed the cake on a plate and tray (with some barriers, a thistle and tea) before bringing it to her mother; but Elinor walked into the kitchen and told Merida that she was worried sick about her. Merida was starting to have second thoughts until her mother told her that "a decision still has to be made" and handed her the cake, by claiming that it was a peace offering that she made herself: nothing happened after the queen took one bite of it and stated to feel sick. Merida wasn't happy of the results as it turned her mother into a bear, so the two headed to the Witch's Cottage so the witch could undo it, but not before leaving Harris, Hubert and Hamish in the kitchen with a half eaten tart. When the two got to the cottage, the witch was no longer there, but she did leave Merida a message about the spell in her cauldron: by the second sun rise Elinor will stay a bear forever if Merida doesn't "mend the bond, torn by pride."

Merida wasn't sure what it mend until the wisps led both her and the queen to the ruins of the "Ancient Kingdom" from the old legend and learned that the oldest prince was the same prince that the witch had told Merida about and that the spell had turned him into the demon bear, Mor'du. The ruins also had a split stone carving of the brothers: just like the Family Tapestry she 'split'. Merida knew what she must do: fix the tapestry and place it over her mother before the second sun rise and before she ends up like Mor'du.

But after King Fergus saw Elinor's born dress and the 'bear' in the castle, he locked his daughter in the tapestry room to keep her safe, while he and the lords went to kill 'it'. As Merida cried for Maudie to unlock the door, three bear cubs (walking on two legs) came up to the lock door and she knew right away that her brothers' sweet teeth got them to eat the rest of the 'spell'. But the three were still able to free their sister and help her save their mother. After Merida and Elinor defeated Mor'du in the stone ring, the sun started to rise and Merida placed the fixed tapestry over her mother to change her back, but nothing happened and Merida started to cry. As Merida told her mother how much she loves her, that she was sorry for what she did and that she knew that she was always there for her, she stopped crying when she felt her mother's hand stroking her hair. Their forgiveness and love for each other undid the spell on both the queen and the triplets.

It may not look like it, but the spell did change Elinor and help Merida understand the true meaning of fate as it made the bond between them stronger than ever.

Once Upon a Time
In Once Upon a Time, it is known as the Spell of Mor'du. After Merida's brothers are captured by the Clan Lords Macintosh, MacGuffin and Dingwall, she recruits Belle to help her save them. The pair enter the Witch's Cottage where Merida uncovers a potion that will help her defeat the Lords. While Merida practices her archery, Belle makes the potion in a liquid form, though is hesitant to give it to her claiming that she doesn't need magic to change fate. When Merida does confront the Clan Lords. Belle switches the potion with a vile of water, though Merida is able to eventually defeat them anyway without the use of the potion, and save her brothers. After the Dark Curse is enacted, Emma captures Merida's heart and takes control of her. In order to make Gold a true hero she orders Merida to kill Belle, in hopes that he will be willing to defend her. She forces Merida to drink the Spell of Mor'du potion and Merida transforms into a bear. Merida chases Belle, but sees Gold and confronts him. He is able to throw some anti-transformation powder into her mouth which undoes the effect of the potion and restores Merida back to her original state.