I forgot, the worst side about it is, if not labeled a parody, who ever does own IP copyright over the images can peruse litigation for infringement. (And implied parody does not legally count.)

Speaking as a person with formal Sequential Art schooling, and not as a member of staff:

Copyright by default goes to the person creating the piece of work, unless you have a contract specifying otherwise. The artist retains all rights, in fact, and can choose to grant their client some of those rights either out of courtesy or for compensation.

One of my SA business instructors told us of a case where she'd been hired to do... I believe it was a postcard illustration, and the organization ended up using the image on their website as well. She promptly sent them an invoice for the additional digital publishing rights, as those had not been part of the original contract. Digital publishing rights in the professional world are also not typically sold on an indefinite basis, but rather as a time-limited service. "Okay, you'll pay me $X to use this image in Y places on your website from 2016-05-01 to 2017-04-30, and if you want to use it longer we'll write a new contract for that" kind of thing.

If you drew a picture of Mickey Mouse and Disney totally loved it, they might contact you to buy the rights off of you. More likely they'd send you a C&D letter and/or sue you for trademark infringement. Trademarks are a completely different kettle of fish, and have very little to do with copyright law.

So please read up on copyright law, to spare yourself future frustration.

As well as: In addition to copyright, visual artists forfeit another set of rights in work-for-hire production. In 1991, Congress passed the Visual Artists Rights Act (VARA), which affirms an artist’s moral right to the continued physical integrity of his or her work after sale. VARA also grants artists the right to have their names associated with their work and only their work and to prevent their names from being associated with their work should it be distorted, mutilated, or modified by someone else. (See www.collegeart.org/ip/qa5.html) These rights, however, do not apply to any artwork created under a work-for-hire arrangement.

Remember that the work-for-hire doctrine in copyright law shifts ownership of intellectual property from creator to employer or the commissioning party.
The distinction between a work-for-hire employee and freelance producer is not always clear-cut. Be certain that all parties agree on your status before you begin work.
Don’t rely on oral agreements. Ask for explicit written contracts that spell out the terms of artist/employer or artist/patron relationships, including ownership of copyrights.

Stanford University's explanation on for-hire works and intellectual properties.

Where as work-for-hire employee is defined as creating the design of another's IP, and freelance producer is creating an IP of your own design.

The rights that do not apply, by the way, are the rights to have the artist's name displayed. Where is is courtesy, it is not law in for-hire-works.

Private commissions rarely-if-ever qualify for work-for-hire status - it's something that typically only comes into play if the purpose of the work is commercial.

So yes, it is part of work-for-hire arrangements that the rights belong to the employer unless contract specifically states otherwise. Absolutely. Doesn't, however, have anything to do with most fandom work.