anvil
From LSJ
subs.
V. ἄκμων, ὁ (Soph., Frag.).
As with a blow upon an anvil, swinging his club above his head, he brought it down upon the child's flaxen head: V. μυδρόκτυπον μίμημʼ ὑπὲρ κάρα βαλών ξύλον καθῆκε παιδὸς ἐς ξανθὸν κάρα (Soph., Frag.).