Losing his pants in LA, carousing in Vancouver - Zac is definitely doing the "change the image" thing.

Zac Efron’s recent wild night in Vancouver went a long way in helping the Disney star shed his “good guy” image, at least for anyone who had to watch it.

Apparently, the 21-year-old teen heartthrob likes to party – and hard. A scene source tells FOX411 that Zac and his pals hit Vancouver hotspot Opus Bar this past weekend ready to rumble, and quickly made their way through what sounds like about half of the bar’s top-shelf brands.

“They were all about partying,” snitches the snitch. “They were downing one Bitter Cherry Salome Sour after another, until they moved on to super strong Belvedere vodka and sodas.”

Then came the Skyy shots. “They looked like they were really celebrating!” said the insider.

Indeed. Apparently Efron made a point to toast every single drink he and his posse downed before stumbling into the night with some staying-upright help from his friends.

Rookie.

Note to Vanessa: maybe building a tiki bar in your home would keep little Zacky a little closer? Oh wait, you’re not 21 yet. Scratch that!

PHOTOS: For more photos of Zac Efron out on the town go to x17online.com.