I think it's a reference to cyanide smelling like almonds. In particular I remember a Jodi Foster movie The little Girl who lives down the Lane where Jodi poisons a rapist. He says, "It tastes like almonds." as he drinks the tea. Jodi Foster says, "It's the almond extract." knowing it's the cyanide.

So the punchline is setup to be something about poison but gets subverted by the hand grenade.

It's an anti-joke. I love it.

Cyanide smells (and maybe tastes?) like almonds. For people aware of this there is a subversion of expectation. It isn't particularly good joke but taken satirically it's alright.

It's called an anti-joke and I found it funny. It was obviously set up that way by the poster.

hugpoint?

Reminds me of the worst opening line contest.

https://www.bulwer-lytton.com/

2023s winner:

She was a beautiful woman; more specifically she was the kind of beautiful woman who had an hourlong skincare routine that made her look either ethereal or like a glazed donut, depending on how attracted to her you were.

naw this is gold

How are you on 196 and unfamiliar with shitposts

It's like the Bulwer-Lytton (writer known for terrible cliche writing, who people intentionally mimic in jest) of two sentence horror.

I genuinely thought it was hilarious. The first sentence is the setup, while the second delivers a misdirection and finishes on an absurd conclusion.

I call it non-medy

I would say the opposite of a punchline is throwing a grenade at a motherfucker