When Tsuyoshi Tozak, director of Bubble Bobble 4 Friends, was asked about if Bub and Bob would appear in the Super Smash Bros. franchise, they simply responded "let's skip that question". The interviewer theorized that they may have been under a non-disclosure agreement, citing a similar response when asking the developers of Cuphead about if they wanted to make a TV cartoon, which would eventually happen, but come the end of Super Smash Bros. Ultimate's DLC cycle, Bubble Bobble content did not appear in any form, meaning that Tozak was likely indifferent on Smash rather than under NDA.