Short answer: You can't, a judge could throw it out of court.
Long answer: Technically, you can come close by signing over the rights to the organization Creative Commons. (They have a form). They will still have to contact you if they want attribution waived. You should recieve a FULL license in exchange.
Why I hate you: Because you'll probably use CC-BY-SA and I'll never be able to put the character in the same comic as Jenny Everywhere.
Why this is important: If you ever get offered a chance to produce a comic for a 3rd party with your character and they pay you for it, it is entirely possible (even likely) that you just lost the rights to your character. Even you would not be allowed to use the character again. A signed, legally binding document overrides all non-signed grants. (This may work to screw over someone with which you have a verbal agreement, but it might render you legally liable for damages, I am not a lawyer, for full details go ask LAWYER-MAN![TM] And his BRIEFS OF JUSTICE[TM].
*pantsless lawyer*
Woah... wrong kind of briefs.
*Guy wearing a suit with no pants, boxers of various design!*
"That's better."
Lawyer-Man[TM] character and license: It's friggin public dah-main beeyatch.
Lawyer-Man[TM] himself is not public domain, he does this to retain trademark rights. Lawyer-Man requires that an appropriate TM symbol (as should be depicted here unless the bbforum is buggy) be placed next to his name. Lawyer-Man does not give legal advice, and a standard disclaimer that Lawyer-Man[TM] is a superhero and not a practicing lawyer in most states should be displayed. To quote Lawyer-Man: "They wouldn't let me practice law without pants."
Lawyer-Man[TM] Furthermore requires that the rights to any and all depictions of him be assigned to either the Creative Commons organization, or his original author. A Quid-Pro-Quo reciprocal grant of license for use of the trademark and depiction of lawyer-man is granted.
Lawyer-Man[TM]'s Arch Nemesis: Man Lawyer[TM], and his evil twin who also claims to be Lawyer-Man[TM] may be depicted with pants. Any depiction of Lawyer-Man with pants is deemed to be either Man-Lawyer[TM], Pod People, a synthoid robot, or a very clever ruse to throw off suspicion.
Finally, nobody recognizes Lawyer-Man[TM] when he's wearing pants, this is derived from his only real superpower... his memory warping, mind bending, mesmerizing, 'BRIEFS OF JUSTICE!!![TM]" Though, he may occasionally be assigned the rights to other superpowers temporarily as parts of civil actions against other superheroes.
Additionally, Lawyer-Man was put here not for the sole purpose of making sure that this thread fit into the 'New Open Source Characters' section, but
Other characters may be created with memory warping underoo's but they are not to be called 'Lawyer-Man'[TM], 'LawyerMan[TM]" or "Lawyer Man[TM] unless they are explicitly this character and the original author may require a reciprocal grant for mind warping undergarments not a part of his 'Lawyer-Man[TM]' Grant.
All depictions of Lawyer-Man are under the LMPL version 1.0 or a creative commons license compatible with Lawyer-Man's license (At current, CC-BY and CC-O, more will be added). All licenses must allow commercial use and may not require reciprocity under a single license (like this one almost does).
V 1.0 of the license will be similar to this post. The license will be updated as necessary to allow it's author to be an egotistical and selfish jerkwad who claims to own the work in spite of it being relatively free (and him being relatively useless), and to permit use subject to reasonable terms.
Additionally, the author (and any company and/or organization he might form now or in the future) is granted a worldwide, royalty free license to sublicense, use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the character with or without pants and/or briefs of justice subject to his own whims. Because of this reciprocal grant the author may be contacted to grant permission to use any version of 'Lawyer-Man[TM] and/or his Briefs of Justice[TM]. Though, like Blender's alternative license, there is no guarantee this will ever happen and it may be retired in the future.
(This is likely necessary in the unlikely event that someone would want to disguise their character as lawyer-man, without losing him/her, and may be necessary under other as yet unforseen circumstances).
Oh, cross universe fusions between 'Jenny Everywhere' and 'Lawyer-Man[TM]' would also need a legal fix.
Subject: How to release characters into the public domain. 
