Flame Wheels are small chariots that appear in Elysium.
Generally appearing in large numbers, Flame Wheels will immediately rush towards Zagreus once they notice him. Their only "attack" is to explode on contact with either Zagreus or a solid object. They will also explode when their health is depleted, making close combat ill-advised.
'...The chariot is a famous symbol of the warfare and technology of my mortal days. However, its specific role in battle sometimes is exaggerated. Chariots ushered men like me to the front lines. They themselves were seldom the ones to go crashing through enemy ranks. Though, there were, indeed, exceptions. More than once I witnessed some particularly brave or bloodthirsty soul abandon his expected duties at the helm of his vessel, and crash explosively into enemy ranks -- like the stories tell. This led to death, of course. But, dying valorously and spectacularly sometimes is sufficient to secure an all-to-decent spot within the afterlife.'
Purchasing the Flame Wheels Release from a Well of Charon in Elysium will prevent Flame Wheels from appearing in encounters.