Creation
In 2013, Carter-Ethan Rankin chose to create 30 new characters that he would voluntarily release into the public domain. The Invisible Pink Unicorn was #19, created as an open source character specifically for use by anyone, following the rules of properties In the Public Domain.
Character Description
Quoted from the Public Domain Super Heroes wiki:
One of the many men of Nazi Germany imprisoned in concentration camps for the crime of simply being homosexual, Inmate #150758 dreamt of the day the war would end and he and the rest of his inmates would smell freedom.
For some, that day came. For him, it was too late.
Somehow re-awakened in the present day, however, he began avenging the cruelty handed down upon people in the name of religion. Relying heavily on science, his methods aren’t always kind but, he believes them in the best interest of those who have been wronged.
– Carter-Ethan Rankin’s description on PDSH
Note on Appearances
Because The Invisible Pink Unicorn is an Open Source Character, and therefore in the Public Domain, he could appear anywhere, used by anyone. Following the rules of Public Domain characters, each creators’ use of Invisible Pink Unicorn has to be different from everyone else’s, so the character would likely not be consistent in characterization from project-to-project.
“Big Tim’s Funny Books” is listed as the publisher simply because they were the first to actually use the character in a comic.
Non-Comic Appearances
Invisible Pink Unicorn appears in the prose short-story A Series of Queer Events, by Callum Phillpott.