Trebonianus Gallus, AE34 of Seleucia ad Calycadnum, Cilicia. 251-253 AD. 

Radiate, draped, and cuirassed bust right.
Athena standing right, thrusting spear at serpentine giant left, 
who is hurling stones. 

SNG Levante 780.

Used with permission of CNG (cngcoins.com).
Electronic Auction 123, lot 45.
Sold for high bid of $220