I am starting a business (car wash). I would like my logo to include a rendering of an animated sponge.
However, I'm concerned about infringing upon the trademark rights of SpongeBob SquarePants. Our current design features a sponge with facial features (eyes and a mouth) as well as arms and legs. Would I be safer if I were to omit the arms and legs?
Consider reading this article, which describes many of the considerations when comparing trademarks for infringement. Likely, you will want to have an attorney review your specific design and give an opinion regarding infringement.
There is no rule that says, if a certain percentage of a trademark is used (or not) there will be infringement or not. Ultimately, if the consumer is confused, or, likely to be confused; there can be a case made for trademark infringement.