Mimlin

Mimlin is the het ship between Madam Mim and Merlin from the The Sword in the Stone fandom.

Canon
When Arthur was turned into a bird by Merlin and had to hide from a hungry hawk, he happened to tumble down the chimney of a hutt in the woods. Madam Mim finds him as a bird and delights in his suffering, but Arthur tells her that he's no bird, he's a boy. When he tells her that Merlin enchanted him, calling him the greatest wizard of all, Mim takes offense to that. She demonstrates her power by singing a song and shapeshifting as she does. As she's done singing, she laments that for being Merlin's pupil, she will have to destroy Arthur and transforms herself into a cat. Just as she catches Arthur, she transforms back and decides wringing his neck will be more fun, but Merlin shows up just in time. Mim decides to play nice and pets Arthur on the head, lying to Merlin that they were just "playing", but Merlin guesses that she was trying to kill Arthur. Mim stops playing around and angrily yells at Merlin just what he would do about it, Merlin responds by challenging her to a "Wizard's Duel".

So Mim lets go of Arthur and the two of them strut outside, Arthur asks Merlin's owl Archimedes what a "Wizard's Duel" is. Archimedes replies that it's a "battle of wits", Merlin and Mim will try to transform themselves into animals in an attempt to destroy each other. Before the duel starts, Mim gives Merlin three rules; 1#: No minerals or vegetables, only animals, #2: No "make-believe" animals, citing "pink dragons", #3: No disappearing. Merlin adds "no cheating" for her specifically.

As the duel starts, Mim immediately breaks her third rule by vanishing and appearing behind Merlin again as a crocodile. However, most of the Wizard's Duel plays out smoothly, with Mim notably preferring larger animals to crush or eat Merlin, with Merlin preferring smaller animals to hide from her or attack her pragmatically. Some notable exceptions include Merlin turning himself into a walrus to crush Mim, but notably showing concern for her when he can't find her beneath him. Mim then cheats and turns herself into a purple dragon, pointing out that she said "pink dragon" and nearly scorches Merlin alive. However, just as she has him in his clutches, Merlin vanishes. Mim cries foul, but Merlin tells her that he's inside her, having transformed himself into a germ of a new illness he just made up. Mim ends up sick and bed-ridden, with Merlin noting that she will be back to her old self in three weeks tops, but opens the ceiling of her hutt prescribing her lots of sunlight. Mim thrashes about in her bed, saying how much she hates sunlight, but Merlin and Arthur leave her be.

Fanon
Mimlin is a rarepair in already small fandom, but it is notable for being the only possible Hero/Villain ship in the movie. People were intrigued by the established history between them and lament that the earlier drafts of the movie with Mim as the central antagonist rather than one of many obstacles were scrapped. People have also noted how much nicer Merlin is to Mim than vice-versa, speculating that they used to be friends.

Currently, there's only one fic about them on AO3, a direct sequel to the movie exploring Merlin looking after Mim during her recovery.

Fandom
FAN FICTION