Back in the mid 2000s, Mercedes-Benz did offer a C55 AMG after an initial C32 AMG but quickly did away with it as the next-generation product was introduced.
From there it became the C63 that we know, love and drift today.
Now that might be reversed.
According to World Car Fans, AMG may be looking at bringing forward its well utilized forced induction unit for the C. That would mean a twin-turbo, 5.5-liter V8 that will likely be detuned so not to step on the E63/CLS63s' toes.
WCF noted that this prototype appears to have wider bumpers and wheel arches, plus larger air intakes.
Perhaps the question shouldn't be if Mercedes will be shoehorning the five and a half liter in there, but whether this is another development car for a possible C63 Black Series sedan.