Silly me.

From the advertising, I’d assumed Jack Black was AWOL from the “Goosebumps” sequel, and missing his ironic turn as kid’s horror novelist R.L. Stine meant that Columbia wasn’t putting a lot of effort into this sequel to the delightful surprise “Goosebumps” was.

Oh, he’s in “Goosebumps 2: Haunted Halloween.”  In last act, basically, too late to make much of a mark on a movie that has nice effects, Ken Jeong to provide supposedly grown up laughs, decent money spent on effects and some seriously dull child actors as leads.

Just like the trailers and TV commercials. So kudos to Sony/Columbia for truth in advertising.

In a different town, Wardenclyffe, New York, another “Stine story COMES to life,” also involving one of his most demonic and derivative creations — Slappy the “demonic” ventriloquist’s dummy.

Yes, Mr. Stine was a “Twilight Zone” fan, back in the day.

Sarah (Madison Iseman of TV’s “Still the King” and other series) is applying to colleges, younger brother Sonny (Jeremy Ray Taylor of “It”) is the bullied nerd in middle school and Sam (Caleel Harris of TV’s “Castle Rock”) is Sonny’s pal and business partner. The “Junk Bros” will haul away your trash for you.

That’s how they get the call to hit the long-abandoned Queen Anne style house down the street, clean it out. And that’s where they stumble across a hidden compartment with an ancient steamer trunk and an untitled book under lock and key inside.

“Who locks up a BOOK?”

Weird. Not as weird as “Slappy,” the dummy they also pick up.

Slappy comes with a card with an incantation written on the back. Next thing you know, he’s acting out, giving the bullies the business and settling scores with Sarah’s faithless boyfriend.

He just wants a “family,” he says. The kids employed to play these youngsters so under-react to this incredible, supernatural occurrence that you’d swear this happens every day in their families.

But not in Wardenclyffe, New York. Even though, if you remember your history, a certain Nicola Tesla once set up show for his experiments with radio and wireless transmission of electricity.

Events progress the way they do in these movies, abruptly. Slappy turns bad and the kids are hard pressed to keep his evil a secret when he sets out to make “Halloween come to life.”

Character actress Wendi McClendon-Covey adds laughs in her few scenes playing the siblings’ single mom, a nursing home nurse. Chris Parnell plays the pharmacist who flirts with her, a waste of a fine comic talent (he has nothing to play).

And Jeong is the single, childless neighbor a little too INTO Halloween, the sort of grownup still into R.L. Stine books.

“Classic ‘Goosebumps’ moment!”

The 2015 “Goosebumps” film had exactly the same story arc, with all manner of Stine mayhem erupting in the third act. The effects — digital witch costumes, Jack-o-Lanterns, mummies and Werewolves spinning to life — are every bit as good.

But the plot feels played and the stakes feel low. Black’s Stine doesn’t show up early enough to lend credence to the incredible, and perhaps show the kids on set how you react when the bully and his boys are nabbed and yanked into the heavens by witches.

The leading trio may have long careers ahead of them, but collectively, they add nothing to this never-really-scary horror movie for the Stine demographic (12-and-under). And they needed to, because Rob Lieber’s script required any spark the cast or once-promising director (Ari Sandel did “West Bank Story” way back when) could give it.

MPAA Rating: PG, mild frights

Cast: Madison Iseman, Jeremy Ray Taylor, Caleel Harris, Wendi McClendon-Covey, Ken Jeong, Chris Parnell, Bryce Cass

Credits:Directed by Ari Sandel, script by Rob Lieber, based on the R.L. Stone books. A Columbia release.

Running time: 1:30