Hey! I'm currently making a parody show of an animated TV series. The original show's premise is teenagers on a remote island doing challenges each week and eliminating one of their own each week until one only is left standing on the island. Now, the show has its' own host and contestants throughout its' many seasons, but MY parody show has a completely different cast but the same host. I AM using the same theme song of the original show for my show, and I am wondering how legal is that? My show is created by myself - the background, the characters, the animation, the script, and so on, but the style of the show is similar to the original show, as well as containing half of its' name in my show's title.
To summarize, I'm using half the show's title, the host as a character on the show (but it is changeable), the same intro song and an additional musical pieces, all are necessary to the recognizability of my series as a parody of the original. Yet, the entire cast is of my own, as well as music (royalty free), sound effects, background and everything else I haven't mentioned is my creation.
Is that legal? If not, what can I add/subtract from the show to make it legal?