KAYNE WEST & KIM KARDASHIAN CELEBRATE HALLOWEEN IN NYC NIGHTCLUB

Watch your back, Ariel, Kim Kardashian makes one sexy mermaid!

The reality star transformed into a beautiful lady of the sea Saturday night at Midori Green's Halloween Party in NYC. Wearing a blonde wig, plenty of pearls and a seashell top, Kim even had a handsome captain—Kanye West, of course—to complete her ensemble. Notably missing, however, was the giant pinky ring she showed off on Wednesday.

"I don't have a ring [tonight]," she said with a smile. When we pressed further for details about that massive sparkler, she added, "It's a pinky ring. Just a ring! Not a big deal."

Fair enough. We know, too, from Kris Jenner, that the impressive gem is not an engagement ring. (And come on, mom would know.)

Kanye, adorably, watched from the sidelines as Kim gave interviews to press on the green carpet. He even charmed reporters by snapping pictures on his iPhone of his brunette-turned-blonde love.

Kim explained why she ditched her trademark dark locks for the night. "It's Halloween, so I thought if I did my regular hair it would just be kind of boring," she said. "And I didn't want to do red hair, like Ariel, because I did red hair with Poison Ivy last year. I just thought it would be fun to do blonde."

As fabulous as she looked, Kim said it only "took about two hours to get ready." She even helped to design her ethereal getup, collaborating with Trashy Lingerie. "It was really fun," she said. "My stylist Monica Rose helped me put it all together."

Once inside the party at Avenue, Kimye enjoyed their drinks in the VIP area with pals including La La Anthony and Simon Huck. Kim and Kanye sang along to the music—including some of 'Ye's hits—danced together, and were quite affectionate throughout the night.