I've shown this unique As of
Caracalla before, in the old Ugly Ducklings
thread. This is the first known appearance of a Departure for
Britain type of 208 AD with accompanying soldiers on a middle bronze of
Caracalla. Such
types are known on
sestertii of Septimius and
Caracalla and on
asses of Septimius, but until now Caracalla's middle bronzes
had only shown the Unaccompanied Emperor on Horseback
type, or Emperor on horseback riding down a kneeling enemy.
I think this coin beats Scott's for Worst preserved, but it might have to bow to Moonmoth's!