From Homestar Runner Wiki
According to Strong Bad, Sweet Cuppin' Cakes is all about The Worm and efforts by Sherlock to get him out of the ground. It would appear that these efforts are generally unsuccessful in the same way that Charlie Brown's attempts to kick the football are, and both characters seem to get upstaged pretty handily by Eh! Steve. The Worm is also attached to a soup pot which is underground.
When the Worm speaks, it does so with a vaguely European accent.