Well, that was actual Sonic, not Ugly Sonic, so probably has nothing to do with Paramount.
(I also know there were a bunch of non-Disney properties in Who Framed Roger Rabbit, but WB had strict rules, for instance, Mickey Mouse and Bugs Bunny had to have the same amount of lines and the same amount of screen time, and a representative measured it down to the millisecond. Also, it seems like the big studios are somehow even more protective with their IP now.)
Didn't Sonic already have a cameo in Wreck it Ralph? Maybe it has something to do with that
Well, that was actual Sonic, not Ugly Sonic, so probably has nothing to do with Paramount.
(I also know there were a bunch of non-Disney properties in Who Framed Roger Rabbit, but WB had strict rules, for instance, Mickey Mouse and Bugs Bunny had to have the same amount of lines and the same amount of screen time, and a representative measured it down to the millisecond. Also, it seems like the big studios are somehow even more protective with their IP now.)