Severus Alexander as Caesar. 221-222 AD. AE 33, 21.13g. Pamphylia, Aspendos. 

Obv: Bare-headed, cuirassed bust right, seen from front, 
drapery on far shoulder, Medusa head on breast of cuirass.
Rev: ACPENDIWN, Triform Hekate standing, wearing kalathos on 
each of her three heads, holding a patera, two torches, and 
three other uncertain objects in her six hands; below, two 
hounds spring left and right below. 
 
Apparently unpublished for Severus Alexander as Caesar: not 
in BM, SNG von Aulock, SNG Cop, Mionnet, four reprinted 
works on Greek coins by Imhoof-Blumer, Lindgren, Kraft's 
System etc. 
Cf. SNG von Aulock 4591 for Julia Soaemias, same reverse die. Good Fine.
Ex Dr. Stephen Gerson Collection.

The portrait is bare-headed, and, as pointed out by Gert 
Boersema in a discussion on Forvm Ancient Coins, shares a 
reverse die with Julia Soaemias, so is presumably of Severus 
Alexander as Caesar under Elagabalus. As on our coin, dogs 
also accompany Hekate on a coin of Maximinus I at 
Themisonion, Phrygia (SNG Aulock 4021). The goddess Hekate 
was said to be accompanied by barking or howling hounds of 
the underworld.

Gemini Numismatic Auction #6, January 10, 2010, lot 644