// Sliver creatures you control have "Whenever this creature attacks, it deals 1 damage to target creature or player."
Ability ability = new AttacksTriggeredAbility(new DamageTargetEffect(1), false);
ability.addTarget(new TargetCreatureOrPlayer());
this.addAbility(new SimpleStaticAbility(Zone.BATTLEFIELD,
new GainAbilityAllEffect(ability,
Duration.WhileOnBattlefield, new FilterControlledCreaturePermanent("Sliver","Sliver creatures"),
"Sliver creatures you control have \"Whenever this creature attacks, it deals 1 damage to target creature or player.\"")));
}