I was reading a British detective story, “The Black Cat”, by Martha Grimes. There was a mention of runcible spoons. And also of a verse, “The Owl and the Pussy-Cat”. Curious, I went to the web and found this:

‘They dined on mince, and slices of quince,
Which they ate with a runcible spoon;
And hand in hand, on the edge of the sand,
They danced by the light of the moon,’
“The Owl and the Pussy-Cat”
—Edward Lear, 1871

And this:
“Upon re-reading this poem as an adult, I am forced to ask: ‘what on Earth is a runcible spoon?’ So, I got to work on some researching, and I was surprised with what I learned. Hopefully, you will be too.

The word runcible, as it turns out, was invented entirely. Supposedly, ‘runcible’ was one of Lear’s favourite nonsense words, which makes sense when you learn that Lear used the term time and time again to describe different things, from a ‘runcible hat’, to a ‘runcible cat’ or ‘runcible goose’. So, the question arises; how do we define ‘runcible’?

Well, with regards to silverware, a runcible spoon has been defined from around the 1920s as more of a rounded fork, featuring three broad, curved tines, and one sharpened edge, frequently used for hors d’oeuvres. Runcible spoons can come in a vast variety of sizes, going from examples small enough to use for eating pickles, to almost comically large items, possibly perfect for dining on mince and slices of quince.”

https://www.google.com/amp/s/b...uncible-spoon/%3famp

The complete poem here:
https://www.jenieyolland.com/w...is-a-runcible-spoon/

Your google link went 404. But based on your description, sounds like a spork.

^^^ First thing I thought, but with a sharpened edge. Prison spork.

Third vote for spork!

Only reference I’ve seen is in Pynchon’s “Gravity’s Rainbow” which has short scene with a fight using “sharpened runcible spoons”