I've lost countless dozens of auctions on his coins, until I finally won one on a very conservative bid!
Rome, Gallic empire
Marius, Spring(?) 269
AE Antoninianus
IMP C M AVR MARIVS AVG, Radiate, draped, and cuirassed bust right
VICTORIA AVG, Victory standing left with wreath and palm
RIC 17

In late 268, Gallic emperor Postumus faced the largest threat to his rule in the form of the usurper Laelianus, headquartered in Mainz. The usurper was defeated in early 269, dead either by Postumus's forces, or killed by his own to secure relief from the seige. Postumus' troops were hungry, weary, and underpaid. They unanimously demanded permission to sack and loot Mainz, which Postumus denied, wishing to stabilize his hold over the area. The soldiers killed Postumus and picked a replacement seemingly at random - an army blacksmith named Marcus Aurelius Marius.
The only source of Marius' life and rule is the notoriously fanciful Historia Augusta. It claims that Marius ruled just three days before being slain in favor of Victorinus - Postumus' right hand man and a more capable administrator than a career blacksmith. It also claims that Marius was slain with a sword of his own making.
Contrary to the three day claims, the fact that Marius's coins utilize an original portrait and were made at more than one mint suggest a reign of at least a month, though admittedly not much longer than that.
All coins of Marius are rare.