Philadelphia Police Department -- Worst PSA Ever!!!

What the heck was the Philadelphia Police Department thinking when they released a video that seems more like a bad trip than an anti-drug PSA?

The PPD must love being the butt of Internet jokes ... 'cause the web is buzzing after they released a PSA featuring an old video from "Saved by the Bell."

They put their photoshop skills on display when they stealthily replaced the face of former NBC chairman, Brandon Tartikoff, with the Philly police commissioner's face in the ad.

Watch the video and see if you can spot the change they made to the original video.