Numerian, son of Carus. 283-284. Radiate. 23 mm.
VNDIQVE VICTORES, emperor standing left holding globe and long vertical scepter
"Everywhere victorious" (a great exaggeration)
IMP NVMERIANVS AVG
Struck 284 at Rome "shortly before his death" (RIC p.126).
Also used by Diocletian and Maximian, but they are extremely rare. So it is NOT unique, but close. Also, I have been shown a coin of his brother Carinus with this type, but that example might just be a unique example and a minting error (a "mule"). In any case, the next example you see of this reverse is highly likely to be of Numerian.