Mabill is the shipping of Mabel Pines and Bill Cipher.
Although it is also criticized by many in the Gravity Falls fandom, it is a considerably popular ship for both characters, maybe not as popular as BillDIp, but one of the most popular Bill Cipher ships.
It has a very strong competition: BillDip (as mentioned in text above) along with Mabifica as a ship people mainly ship alongside BillDip pairing.
Refer to Reverse Mabill for its Reverse Falls counterpart.
Mabel and Bill are similar in the respect that they both like to have fun (although Bill's idea of fun is chaos), and Bill has canonically said in Dipper and Mabel's Guide to Mystery and Nonstop Fun that he likes Mabel more than Dipper. Whether platonic or romantic, interactions between them are commonly lighthearted, such as goofing off, playing pranks, doing silly things, and laughing together.
Bill did not force Mabel to survive through Weirdmageddon; instead, he gave her paradise. Their original deal was: if Mabel gave him the rift, she'd get a few more days of summer. Bill gave her an eternal paradise filled with creatures from her imagination.
Depictions of how Bill and Mabel may interact can range from endearing narratives of Mabel teaching Bill what love is or making him her new 'summer romance'. Mabel is also shown to be understanding and sympathetic, so fans believe if a Pines were to be kind to Bill and attempt to redeem him, it would be Mabel. However, the ship can be portrayed in a darker light as well, where Bill's villainous nature comes into play: such as manipulating the notably trusting Mabel, pulling her into a one-sided romance for his own personal gain, risqué imagery of gore and degenerate consequences of Mabel's decision to date a demon.
Ryouhiko-Ankuu : fanartist.
count-the-shooting-stars (fanfiction author)