We honestly don’t know where to begin. How to describe That’s My Boy? How to convey quite how crass, how stupid, how offensive and how cataclysmically unfunny this film is? It’s tricky. It really is. But we think one phrase might just cover it; might just give you some idea of what’s going on here. That’s My Boy might be the worst film Adam Sandler has ever made.

Just let that sink in for a moment. Let it settle. Still with us? Okay. Then we will begin.

The plot of That’s My Boy is – like many Adam Sandler movies – about a dysfunctional man-child trying to reconnect with his actual child, in this instance, a grown-up Andy Samberg, about to be married. The story begins with Sandler’s Donny in school. It’s important to stress that by school, we mean school. Not high-school. Not college. School. For context (the necessity of which will soon become apparent), the actor playing young Donny is 15 years old, but if anything, he’s playing younger than that in this film.

Young Donny has a crush on his teacher. Nothing uncommon there; plenty of kids approaching puberty latch onto an older, unobtainable woman to crush on. What’s a little more un-common – and more than a little troubling – is that the teacher in question reciprocates. The teacher takes him into the back office and bangs him. The teacher leaves cute notes on his homework (“I’m going to sit on your face tonight!”), and no matter how long you wait for the punch-line, or for the dream-sequence to end, it doesn’t. And thus the plot of the movie begins with pedophilia and the statutory rape of a minor. That we didn’t walk out of the cinema there and then, at 10 minutes in, was an act of masochistic self-punishment above-and-beyond the call of duty. Because things only get worse from there. Much, much worse.

Skip forward 30 years, and – much like Ted from, er, Ted – Donny’s brief moment in the spotlight (because a kid banging his teacher and impregnating her apparently makes you a cult hero) has faded, and he’s stuck in a state of arrested development. He’s also stuck with a hefty bill from the IRS, and tries to reconnect with the son who disowned him, and grew up normal – relatively speaking – in a cynical attempt to settle those debts.

Speaking – inevitably – with a stupid fucking voice, Sandler’s Donny is a horrible creation. His Boston accent, and awful, child-like way of speaking – not to mention an appalling wig – make him a detestable figure. Quite why, when he begins systematically ruining his son’s life, everyone warms to him and treats him like the life-and-soul is as baffling to the audience as it is to Samberg’s character.

Samberg tries his best to wring some comedy out of proceedings as the straight-man, but he’s fighting a losing battle. The principal notion of humour in That’s My Boy is that people saying “dick” and “vagina” a lot is an avenue to instant hilarity. It’s not. A vastly over-weight stripper spends the film scantily clad with her tits hanging out, even eating during dance routines. Why? Because fat people are funny, you see? The ‘Grandma’ character, an aged old woman, is portrayed as a promiscuous whore, whom half the male cast have sex with throughout the tortuously bloated 116min run-time. You’re laughing already, aren’t you?

How about a scene of Donny masturbating over said grandma’s picture, while talking us all through it in that stupid fucking voice? Or this hilarious zinger from Samberg’s wealthy father-in-law; “All my staff are lucky to be in the country, so feel free to abuse the shit out of them.” What larks!

That’s what people want in their films, is it? We might as well call time on this medium now.

Are there any redeeming features? Well, Will Forte does good work in a limited role, while the highlight is Milo Ventimiglia, who is great playing somewhat against type as a tough, ripped army jock. And I suppose there’s some fun to be had with Vanilla Ice playing himself. There’s even a brief glimpse of a real film shining through, as Donny and his son have a moment of quiet reconciliation, and they talk to each other like actual human beings (the only time anyone does, in the entire film). But it doesn’t last long, and we’re soon back to Donny trying to resurrect the old Budweiser ads’ “whassssssuuuuuuuuup!” catchphrase. That the film goes to this well so frequently for humour should be indicative of it’s astounding laziness.

Worst of all? There’s a twist at the end that is so mindbogglingly ridiculous, so astonishingly inappropriate as to render the rest of the film tame and measured by comparison. It’s the most gob-smacking thing you’ll see in a film all year, in the worst possible way. Once again, you won’t believe that the film is ACTUALLY going there, but it does. It’s intensely uncomfortable for all concerned. The way the film makes light of – even celebrates – issues like rape, pedophilia, incest is reprehensible to the extreme.

South Park once did an episode, many moons ago, tearing the career of Rob Schneider to shreds (“Rob Schneider is… A stapler!”), but the same can now be applied to Adam Sandler. His is the lowest common denominator of humour, and whatever sway he might once have held over audiences (there’s still a lot of love out there for Happy Gilmore), should finally be erased forever by anyone unfortunate enough to lay eyes on this disaster.

Sometimes referring to a comedy as “offensive” is used as a compliment, but not here. Here it’s for real. That’s My Boy is the most offensive, lazy, crass and un-funny comedy you might ever see. That this film got made should be taken as a personal insult by every single person who’s ever seen a film.

Come back, Rob Schneider, all is forgiven.