The Transformation

Confirmed, re: the posts made by @miracle-bug, @miraculeusecoccinelle, and @catnoir-s.

That said, I seemed to recall something about the creation of transformative works back when anime FMVs (and some fanfiction) were suffering the same, so I went to look it up. Wiki, at least, has offered me the following:

In United States copyright law, transformation is a possible justification that use of a copyrighted work may qualify as fair use, i.e., that a certain use of a work does not infringe its holder’s copyright due to the public interest in the usage. Transformation is an important issue in deciding whether a use meets the first factor of the fair-use test, and is generally critical for determining whether a use is in fact fair, although no one factor is dispositive.

A key consideration in recent fair use cases is the extent to which the use is transformative. In the 1994 decision Campbell v. Acuff-Rose Music Inc,[6] the U.S. Supreme Court held that when the purpose of the use is transformative, this makes the first factor more likely to favor fair use.[7]  …Blanch v. Koons is another example of a fair use case that focused on transformativeness. In 2006, Jeff Koons used a photograph taken by commercial photographer Andrea Blanch in a collage painting.[8] He appropriated a central portion of an advertisement she had been commissioned to shoot for a magazine. Koons prevailed in part because his use was found transformative under the first fair use factor.

Generally, use of a work to comment on the work itself somehow will qualify as transformative. Quoting portions of a work to criticize it, as in a book review, is transformative. Likewise, parody is transformative — repurposing a work to mock the work itself or the principles the work represents serves a very different purpose from that of the original work.

The Campbell court held that hip-hop group 2 Live Crew’s parody of the song “Oh, Pretty Woman” was fair use, even though the parody was sold for profit. Thus, having a commercial purpose does not preclude a use from being found fair, even though it makes it less likely.[9] Likewise, the noncommercial purpose of a use makes it more likely to be found a fair use, but it does not make it a fair use automatically.[9]

There have been some attempts to amend DMCA law, like the FAIR USE Act, but it looks like all of them have been stopped in court so far.

Basically it’s a big gray case-by-case area, in US copyright law at least. Though with the parody allowances it sounds like the ML Vine parodies might actually be safest (@caprette lucked out).

Imagine having been in a relationship with Loki for quite some time now, and you really feel like you love him. Except you’re starting to feel that you only like girls. You don’t tell Loki for the longest time because you don’t want to ruin what you have with him, but eventually it becomes too much and you finally confide in him. He takes your admission far better then you had imagined, flashing you that smile of his, laughing a little, before proceeding to transform himself into Lady Loki.