You know it's getting serious when you bust out the his and hers Halloween costumes!

Khloe Kardashian and boyfriend Tristan Thompson had fun celebrating Halloween over the weekend, dressing up together in Marvel Comics-inspired get-ups. Khloe made for an amazing Storm -- complete with white hair and glowing eyes-- while Tristan committed to a full-body Black Panther costume.

"Storm and by boo Black Panther," 32-year-old Khloe Snapchatted.

PICS: Best Halloween Costumes of 2016

Khloe and the 25-year-old Cleveland Cavaliers star weren't shy about showing some PDA, making out and getting hot and heavy on the dance floor at the Halloween bash.

... But let's take a moment to admire their seriously awesome costumes.

Khloe and Tristan have been linked together since early September, and have showed no signs of slowing down. The Keeping Up With the Kardashians star was there for her man in Cleveland, Ohio, last week, when he received his NBA championship ring.

WATCH: EXCLUSIVE: Kris Jenner Officially Approves of Tristan Thompson -- 'He's a Wonderful Guy'

Last month, a source close to Khloe told ET that the two are definitely super into each other.

"They're taking it slow, day by day, but are having so much fun together," the source said about the attractive pair. "It’s still the honeymoon stages and they both have a huge crush on each other."

"He's the nicest, sweetest guy," the source added about the Canadian NBA star. "He comes from a very strong family and has a tight circle of close friends. He really isn't into the 'celeb scene' and does his own thing. He's close friends with [his Cleveland Cavaliers teammate] LeBron [James] and a couple of his teammates."

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Best Halloween Costumes of 2016