this.expansionSetCode = "ZEN";
// When Khalni Gem enters the battlefield, return two lands you control to their owner's hand.
Ability etbAbility = new EntersBattlefieldTriggeredAbility(new KhalniGemReturnToHandTargetEffect());
Target target = new TargetControlledPermanent(2, 2, filter, false);
etbAbility.addTarget(target);
this.addAbility(etbAbility);
// {tap}: Add two mana of any one color to your mana pool.
SimpleManaAbility ability = new SimpleManaAbility(Zone.BATTLEFIELD, new AddManaOfAnyColorEffect(2), new TapSourceCost());
this.addAbility(ability);
}