Hydra's Wail

Once per battle, at the start of the battle round, if a model with this Relic is on the battlefield it can activate the Hydra’s Wail. Until the end of the battle round, when your opponent spends Command Points to use a Stratagem, roll one D6; on a 4+ your opponent must spend one extra Command Point to use that Stratagem, or else it has no effect and the Command Points spent so far are lost.