ability.addTarget(new TargetCreaturePermanent(filter));
this.addAbility(ability);
// {U}{R}: Cromat gains flying until end of turn.
this.addAbility(new SimpleActivatedAbility(Zone.BATTLEFIELD, new GainAbilitySourceEffect(FlyingAbility.getInstance(), Duration.EndOfTurn), new ManaCostsImpl("{U}{R}")));
// {B}{G}: Regenerate Cromat.
this.addAbility(new SimpleActivatedAbility(Zone.BATTLEFIELD, new RegenerateSourceEffect(), new ManaCostsImpl("{B}{G}")));
// {R}{W}: Cromat gets +1/+1 until end of turn.
this.addAbility(new SimpleActivatedAbility(Zone.BATTLEFIELD, new BoostSourceEffect(1,1, Duration.EndOfTurn), new ManaCostsImpl("{R}{W}")));
// {G}{U}: Put Cromat on top of its owner's library.
this.addAbility(new SimpleActivatedAbility(Zone.BATTLEFIELD, new PutOnLibrarySourceEffect(true), new ManaCostsImpl("{G}{U}")));
}