// Defender
this.addAbility(DefenderAbility.getInstance());
// Sacrifice Tinder Wall: Add {R}{R} to your mana pool.
this.addAbility(new SimpleManaAbility(Zone.BATTLEFIELD, new BasicManaEffect(Mana.RedMana(2)), new SacrificeSourceCost()));
// {R}, Sacrifice Tinder Wall: Tinder Wall deals 2 damage to target creature it's blocking.
FilterAttackingCreature filter = new FilterAttackingCreature("creature it's blocking");
filter.add(new BlockingByPredicate(this.getId()));
Ability ability = new SimpleActivatedAbility(Zone.BATTLEFIELD, new DamageTargetEffect(2), new ManaCostsImpl("{R}"));
ability.addTarget(new TargetCreaturePermanent(filter));
ability.addCost(new SacrificeSourceCost());
this.addAbility(ability);