ASM Water

public someclass {
    public static void waterInHell(World world, int x, int y, int z) {
        Block b = world.getBlock(x, y, z);
        if (b.blockMaterial != Material.water) {
            return;
        }
        if (world.provider.isHellWorld) {
            world.setBlockToAir(x, y, z);
            world.playAuxSFX(1004, x, y, z, 0);
            world.playAuxSFX(2000, x, y, z, 4);
        }
    }
}

/* somewhere in your ASM transformer */

    MethodNode method = ASMHelper.findMethod(classNode, "/*TODO: get obf name*/", "onBlockAdded", VOID_TYPE, WORLD_TYPE, INT_TYPE, INT_TYPE, INT_TYPE);
    InsnList patch = new InsnList();
    patch.add(new VarInsnNode(ALOAD, 1));
    patch.add(new VarInsnNode(ILOAD, 2));
    patch.add(new VarInsnNode(ILOAD, 3));
    patch.add(new VarInsnNode(ILOAD, 4));
    patch.add(new MethodInsnNode(INVOKESTATIC, "cofh/asm/whatever/someclass", "waterInHell", getMethodDescriptor(VOID_TYPE, WORLD_TYPE, INT_TYPE, INT_TYPE, INT_TYPE)));