Six Flags Fright Fest
A commercial for the Fright Fest of Six Flags is a video aired in 2016, with a unique placement for a screamer.
The ad starts as a normal ad, with people enjoying the park, and a woman voice over saying: "There's something for everyone at Six Flags". However, exactly 3 seconds in, a monster clown appears and roars, before cutting to creepy imagery and a different male announcer advertising the haunted attraction for the rest of the ad.
NOTE: The following video contains a screamer!