Citations:Mad Swan

Proper noun: "(fandom slang) the ship of characters Jefferson (a.k.a. the Mad Hatter) and Emma Swan from the television series Once Upon a Time"

 * 2015, Katharine E. McCain, "Canon Vs. 'Fanon': Genre Devices In Contemporary Fanfiction", thesis submitted to Georgetown University, page 53:
 * These portmanteaus work around a logistical difficulty while also referencing a notable characteristic of the ship itself, such as the fact that some fans see “Mad Swan” as an odd ship even by fandom standards,