I know this topic's probably been brought up before, but with the Ultimate forms returning in Omniverse, maybe we could discuss what hypothetical Ultimate forms the other Omnitrix aliens could have. I'll start us off:
Ultimate Ripjaws: More muscular than Ripjaws, with gray skin, a fin on his back, and an elongated, shark-like snout, with larger teeth. He's stronger and a faster swimmer, with his bite able to tear through almost anything. He can even pull out his teeth (which are quickly replaced by new ones) and use them as weapons.
Ultimate Upchuck: Possesses a taller, more humanoid form. The bulbs on his back are now stegosaurus-style plates, and he has an extra mouth in both palms, enabling him to eat and regurgitate three times as much. He is also stronger and more agile than regular Upchuck.
Ultimate Goop: A smoother-looking version of Goop (practically see-through). He no longer needs an anti-gravity projector. He hovers in mid-air, and his limbs float separately from his main body (like Lodestar's head), able to fly out and attack enemies under his mental control. Ultimate Goop actually does have the ability to make his slime acidic, and can even solidify it, for hard-hitting punches.
Ultimate Astrodactyl: A more streamlined version of Astrodactyl. His wings are part of his arms, and he has two jets on his back. Instead of whips, his wrists now fire heat-seeking star bolts.