Justin Bieber, girlfriend Selena Gomez, Cody Simpson, director Alfredo Flores and a few other friends visited Goretorium in Las Vegas on Sunday.
Bieber, Gomez and friends met up with creator Eli Roth at 1:30 p.m. for a private tour of the frightening venue.
Roth, who is also the brains behind horror films Hostel and Cabin Fever, created Goretorium as a self-guided multi-level maze of horrors.
The group started off in the lobby of the mythical Delmont hotel but as they toured the space, more and more gruesome sights were revealed.
"Once the group made it out 'alive' they toured the Goretorium retail shop, which is filled with horror props," an onlooker tells PEOPLE.
Looks like the fright-fest helped scare the illness out of Bieber, who got sick on stage while performing the previous night.
Had the best time at Eli Roth's @goretorium! It's Halloween in Vegas everyday over there. So scary. Check it out!— Alfredo Flores (@AlfredoFlores) September 30, 2012
– Mark Gray