Sonic/South Park

Casts:

 * Knuckles as Stan
 * Shadow as Kyle
 * Sonic as Cartman
 * Silver as Kenny
 * Tails as Butter
 * Tikal as Wendy
 * Big as Chef

Explanations:

 * Knuckles is a in love with Vanilla
 * Shadow is a Knuckles' best friend
 * Sonic is a fat as his ego
 * Silver is a lot of accidents
 * Tails is a frequently scoloded.
 * Big is a chef.