By Meghan Blalock
Updated Oct 29, 2012 @ 10:00 am
Jessica Alba Kim Kardashian Stacy Keibler
Credit: Courtesy of Jessica Alba/Twitter; Getty Images (2)

This past weekend saw the start of Halloween parties across the country, which meant celebrities pulled out their best costumes for the spooky soirees. Kim Kardashian (following her own advice) dressed up as a platinum blonde mermaid for the Midori party she hosted in New York (with Kanye West as her sea captain), Jessica Alba and her troupe transformed into the cast of Pixar's The Incredibles in Hollywood, and Stacy Keibler became a masked maven in Las Vegas. Click through the gallery below to see more celebrities in costume!