On YouTube they used to be a flash animation with the main character being a sprite mario or sonic, they were singing with some weird stuff happening in the background with one of the chorus being "this is your life. This is your life. This is your life, don't get any better than this
In the late 90s & very early 2000s, Sprite Comics were popular. Some of the more ambitious creators made animated ones. The only ones I remember with Sonic are "My Tomato" & "That's My Sonic" by Psyguy.