Right anyway let me give you the 4-1-1 on the Bowser Sonic matchup.
It. Is. Scary. For both players, this is not a matchup I would call in anyone's favor because once Sonic is no longer in control, for any reason, that should justifiably be a stock for him. On the reverse, once Sonic breaks through the armor frames, that's game over for Bowser.
Bowser's Flame Cancel is very useful for keeping spin approaches on the low, and I've learned that if you tilt your Shield toward Sonic if he tries to approach with DownB, you can UpB OoS and horridly wreck Sonic's day. If Sonic actually gets you in the air and you're in control of Bowser, Nair is not so much 'Good in this matchup' and more 'the only way you're not dying.' Fair can be a great 'get away from me' move, but if Sonic has to stretch a little further for his combo than your hitstun has you in, your nair is gonna break him. A well timed nair breaks utilt strings, as well, but if you're in low percent you should be crouch cancelling anyway. CC UpB is a good way to deal with Sonic's SideB. Fountain of Dreams is probably Bowser's best chance, because it's unusually high ceiling and moving platforms can help Bowser weave through danger and nail his bair, which is probably the best kill move/setup against Sonic if you can hit him with the strongest hitbox. Not to mention if the platforms aren't raised the highest they can be, Bowser's getup attack is even more safe than normal.