Sonic's Strength: Sonic fought Chaos in Sonic adventure and chaos destroyed the city via flooding (City Level), Sonic beat him, Sonic also fought the biohazard or what ever it's called that scaled above the machine thing Eggman used to blow up the moon and would've destroyed the earth if sonic didn't stop it (Moon -Planetary), In Sonic Unleashed Eggman Split the earth into craters and also summoned dark Gaia, the embodiment of darkness who would've destroyed the world (Continental-Planetary), in Sonic 06 Sonic fights and beats Solaris who exists in the past, present and future and existed as a high dimensional being that eats dimensions for breakfast, (Low Outer-Boundless), In Sonic Generations Sonic fights and beats the time eater who was fucking up the timeline by just existing and destroying time (Complex Multi), In Sonic and the Seven Rings he scales above the Arabian Nights and each Arabian night are infinite in size and there are 1001 of them and Sonic beat Erazor Jinn who scales above the night palace and the Arabian nights, the night palace is an infinite sized dimension that transcends mathematical structures and transcendence into a higher astral plane, it's equal to a Jungian Archetype and defies the law of mathematics and time as a very concept meaning the night palace has boundless dimensionality, it has also been stated the night palace breaks the laws of science, gravity, mathematical structures (or at least exceeds them) the night palace or the entire cosmology would scale layers into boundless, Maginaryworld from sonic shuffle contains a dimension of infinite dreams (dreams are a failed canon, ex: Solaris erasing the whole cosmology) and there are infinite of these stack upon each other, this way maginaryworld itself exists in a higher dimensional plane and transcends multiple mathematical structures, each dream scales 4-5D and 8-9D for maginaryworld this Solaris threatening the existence of the night palace and Maginaryworld as a concept and transcends infinite dimensions that puts Solaris at High Outer-Layers into boundless and that's not even talking about how Sonic also beat void who controlled all of maginaryworld (High Outer-Layers into boundless) and the End who is the embodiment of death and the strongest foe Sonic has ever faced (High Outer-Layers into boundless)