Vanilla Ice is back, back baby.

And for that crime alone, Adam Sandler should get the chair.

Alas, it’s a minor offense in "That’s My Boy," a no-holds-barred raunch-fest that combines bits of "Saturday Night Live" skits and "The Hangover" with every ugly Sandler laugher ever made.

When your comedy starts with a criminally "inappropriate" sexual relationship between a 13 year-old boy and his bombshell teacher, the scariest thought is "Yeah, they’re going to have to top that." Which they then proceed to do.

Sandler has made worse movies, but never one as grotesque as this.

He stars as Donny Berger, who became famous — notorious — in the ’80s for his illegal fling with Miss McGarricle (Eva Amurri Martino). Donny made a lot of money being the kid who lived Van Halen’s "Hot for Teacher" fantasy — the envy of his (male) peers. Of course, he blew through all that cash. Thirty years later, all he has to show for the glory days are a dated TV movie about the affair, his old Fiero and a whopping tax bill.

Donny’s one hope — find his estranged son, whom he named "Han Solo Berger," and stage a reunion with the kid and the imprisoned mom on a sleazy TV show hosted by a guy played by sportscaster/Sandler pal Dan Patrick, sporting freakier hair than usual.

Han Solo changed his name to Todd Peterson and grew up to be a dull hedge-fund manager. Todd’s a pushover, the sort of nerd who makes unfunny "beep beep" computer noises when he’s showing off his math skills.

"Are you sure you’re not a Chinaman?" his insensitive future in-laws want to know.

You will not believe how unfunny "Saturday Night Live’s" Andy Samberg can be until you see this guy — a henpecked groom about to marry the shrill Jamie (Leighton Meester).

Tony Orlando plays Todd’s crude and lewd boss. James Caan does the worst Irish accent he could manage, playing a two-fisted priest who will marry the couple.

There are a staggering number of shock-for-shock’s-sake scenes that go on, ad nauseum — masturbation jokes that don’t land, clumsy, slow showcase moments for the growing number of clowns on Sandler’s payroll (assorted "Saturday Night Live" alumni, Nick Swardson, etc.) all playing caricatures.

And through it all, a much-heavier Sandler waddles and chews on a "Pahk the caah in the chow-duh" Massachusetts accent, reviving the "Wasssuuppppp" catchphrase, aiming low and sometimes hitting his targets. Maybe the best joke is how "good looking" and "sexy" all the women say he is, how charmed every character seems by his oafishness.

The septic tank of a script undercuts its central thesis — that it’s never too late to learn to be a dad, that there’s nothing wrong with being a childish moron, even as a parent — at every turn. Todd can’t ride a bike, can’t play sports and carries spare underwear with him because of assorted childhood traumas.

Fans of lower-than-low comedy may choke on their popcorn over every staggering vulgarity. But sentient beings will find a laugh, here and there, as well. The first reunion-with-Vanilla Ice moment — he and Donny were buds back in the day — is awkward, accusatory and hilarious. And the riotous post-bachelor party bacchanal that Donny throws for his son (with Ice in tow) is cut into a music-video montage that amuses.

But mostly, "That’s My Boy" is a groaner. Yet it’s more appropriate for Father’s Day than you’d think. It’s your aging dad, stuck in the past, swearing and carrying on like he’s just heard about those other guys stealing Mike Tyson’s tiger, assuring you he can top it. As if anybody really wants to see that.