Fans of SM artists took over Twitter on October 31 as they enjoyed this year’s Halloween party, also known as SMTOWN Wonderland!

Many of the top 10 worldwide trending topics that evening were about the event, including #SMTOWNWONDERLAND trending at No. 2, just below #HappyHalloween.

The annual bash featured many memorable moments this year, and the agency has already shared official photos from the event. There were also plenty of images and videos coming in live — although it was a bit hard to decipher them at first.

The biggest mystery of the year was who was underneath that adorable Groot costume! “Groot” even trended worldwide as people wondered which SM artist it could be, and so many memes were born around Groot’s endearing dedication to the event and struggles in the outfit.

Officially a meme.

In the end, it turned out that Groot was none other than f(x)’s Luna, and she came in second place in the costume competition!

Another trending topic worldwide was Chenle after the NCT member was spotted dressed as Pennywise from “It” — chilling and amazing fans.

Speaking of SHINee’s Key, this year was also the birth of “Keydemort” when he dressed up in an incredible Voldemort costume. Although he wasn’t able to attend at first, he created cardboard cut-outs of himself to send to the event, which his group mate Onew helpfully showed off to everyone. Key later stopped by to take photos with the cut-outs.

Key grabbed first place in the costume contest (with Onew taking third), earning recognition for his long run of epic costumes.

Key’s wasn’t the only “Harry Potter”-inspired costume this year, as Girls’ Generation’s Sunny came dressed as Nagini. Fans imagined a match-up between these two sets of SMTOWN artists from past and present parties!

NCT’s Ten also wowed in his costume as Mona Lisa, bringing back memories of when he stood in front of the painting itself.

Girls’ Generation’s Taeyeon gave many fans goose bumps as well with her incredible take on Annabelle.

Meanwhile, NCT continued their couple costume tradition when Jungwoo and Jaehyun arrived as Rose and Jack from “Titanic,” and Jungwoo also became a trending topic worldwide.

A squad of minions united on Halloween, complete with NCT’s Kun, Girls’ Generation’s Yuri, and EXO’s Xiumin, and a fan helpfully put them all together.

Meanwhile, many people noticed the difference in the costume themes chosen by EXO’s Kim brothers this year.

Sometimes memes really do come true (thanks NCT’s Lucas).

Red Velvet’s Irene had fans losing it over her cuteness.

And overall, everyone was loving how Red Velvet has become known for picking interesting and creative costumes!

Fans sometimes aren’t 100 percent sure what the artists are referencing with their costumes, but this interpretation for Super Junior’s Donghae could definitely work (others are guessing he may be the protagonist of the film “Crows Zero”).

Of course, there were some beloved idols missing from the event whose absence was felt.

SMTOWN Wonderland also gives artists a good chance to show their duality.

And Yuri’s face when she saw Baekhyun’s costume could definitely be a meme itself.

Which costume do you think is the most memorable from SM’s 2018 Halloween party?