Myrmidons will copy the Attack points from the last card with attack points added to the player's field, replacing it's own. This ability will only activate when the card is initially purchased and will disable after. These points will carry over to subsequent rounds.
Myrmidons were a legendary people of Greek mythology who, according legend, were created by Zeus from a colony of ants after a plague sent by Hera wiped out the population of the island Aegina. During the Trojan War, they were commanded by Achilles, as described in Homer's Iliad.