DynamicValue xValue = new ManacostVariableValue();
this.getSpellAbility().addEffect(new DamageMultiEffect(xValue));
this.getSpellAbility().addTarget(new TargetCreatureOrPlayerAmount(xValue));
// Flashback-{R}{R}, Discard X cards.
Ability ability = new FlashbackAbility(new ManaCostsImpl("{R}{R}"), TimingRule.SORCERY);
ability.addCost(new DiscardXTargetCost(new FilterCard("cards")));
this.addAbility(ability);
}