Metal Sonic MUST be defeated FIRST during the fight's second phase, as Eggman is technically invincible during this. Sonic, he'll go bouncing around until he either hits the Submarine Mobile, or stops after a few seconds of bouncing. If spin dashed into, much like Silver/Robo/Mecha/Etc. He'll also try to roll up into a ball to hit the unwary player and make them lose rings. Also, after the first phase, Robotnik/Eggman will deploy Metal Sonic for the rest of the fight, who will try to defeat Sonic using either the first or second parts of his famous Overclock ability, or just ramming into Sonic. Instead of small pellets shot out of the sides like in the original, this one uses a more condensed version of Mega-Watt's electricity beam, and there are also variants for the attack if rotated at certain angles. It hovers much like the original, however, this one can hover MUCH higher than the original, the result being that this one can hover like the Egg Mobile from other Sonic titles. It still retains many of its classic traits, but it actually has an ENTIRELY new attack set. This is pretty much a long-awaited overhaul of the Submarine Mobile from the Game Gear, as mentioned. So, with that being said, the final product of the transfer awaits! Now, the cockpit for the Spider-Mobile is INVERTED, and this is why i didn't see the similarity before actually looking between the two images.

See the cockpit? It reminded me of Game Gear's Sonic 1 Bridge Zone boss, as shown in the second attachment: I realized something while playing Sonic Mania that influenced me to do this certain edit, and that's thanks to the Spider-Mobile from Flying Battery Zone Act 2. Since i don't do well making my own sprites, i decided to edit sprites instead.

Sonic 1 ball sprite