A brother made good on a promise his sister never cared for.

Well, at least he is dependable.

A Buzzfeed article highlighted the antics of Mendl Weinstock, who five years ago promised his sister he would bring a llama to her wedding.

The bizarre pledge stemmed from a joke when Mendi teased his sister Riva during a road trip from their home in Ohio to Indiana.

According to Mendi, Riva was prattling on about her future wedding even though she was 17 and single at the time.

"She was talking about her wedding, planning it, making plans almost as if it was going to happen the next day even though she wasn't dating anybody at the time."

To burst her bubble, Mendi said:

"Just to tick her off I said I wasn't going to come to the wedding."

When she told him she did not appreciate the comment, he went further and stipulated:

"If you make me come to the wedding I'm going to bring a llama with me."

So how did he arrive at such a ridiculous undertaking?

"It was just the first thing that popped into my head."

Riva was not amused, but gave in to the joke and said:

"I give up. The llama is invited to the wedding."

Much to her chagrin, Riva realized five years later that her big brother was not kidding during that road trip.

He posted a photo attending Riva's wedding with his four-legged plus-one on Reddit, where it blew up with over 155K upvotes in two days.

Riva had gotten engaged in October, and she shared the exciting news with her brother.

An hour later, she received a text with the confirmation of a llama rental Mendi had arranged with a llama farm near Cleveland for $400.

Riva described one of Mendi's bewitching attributes.

"When my brother puts his mind to something, he gets it done. So at some point I had to accept it and decide that it was easier to get in on the joke than to fight it."

The male llama, named Shockey, even arrived in a custom-made tuxedo, complete with a yarmulke on his head.

At $400, one would think that is steep price for a 21 year-old college student to spend on a prank.

But Mendi disagreed.

"It was so worth it. I mean it was worth it just to see her reaction, but it's been more worth it now that I've gotten all this internet fame."

Even though Riva was expecting the gentle wedding-crasher among the attendees, the sight was still staggering.

Mendi recalled witnessing the precise moment that was worth every penny.

"My sister walked outside and had this humongous gaping looking on her face. There's nothing that can really prepare you for walking outside and seeing a llama."

The llama stayed away from the wedding hall on Sunday but was a popular photo spot outside.

Riva said she took one photo with Shockey and resumed with her bridal duties, but the llama continued delighting guests for a couple of hours.

Riva admitted:

"I was not too thrilled. I think my face in the picture pretty much wraps it up."

For the record, weddings and llamas are apparently a winning combo.

Riva is not upset and even admitted that Shockey made her wedding more special.

Mendi commented:

"She might have been a little mad at first, but she was in on the joke and she definitely realized it was funny and she hasn't held a grudge or anything."

However, it was game on for Riva.

With Mendi's graduation around the corner, l'il sis plotted her next move.

"I've definitely started planning my revenge. He should sleep with one eye open."

Will it be a mule with a cap and gown? We will have to wait and see for a followup on Reddit.

One thing is certain—the Weinstock siblings are sure to deliver on their wacky promises.