Kata

Any specific suggestions? Looks correct to me.

IMO the description is really hard to understand. Only thanks to Chrono's comment I managed to figure out that you have to process an 8-characters-long word, search for resulting 6-characters-long word in the array, and if it can be found return both words. A list of direct instructions would help a lot more than you're given an array... find a pair of words which solve the puzzle... imagine you process a word... you'll get another word. What is it?.

The array exists, but only in the Attempt tests. Still, no arguments and it's not clear what to return: an array with 2 subarrays? The 3rd error message is not helpful at all. Do we need an argument in the function?

It seems you saw my comment before I edited it, I've figured out that array exists on attempt only.

The 3rd error message is not helpful at all

You don't have to write random tests if your fixed tests are already impossible to pass.

I think I'm starting to get what the author wants, return an array with the 8 letters word that after the mentioned transformation becomes a 6 letter word present in the array (this one is the second element of the returned array.)

Do we need an argument in the function

Nope, function apparelShift(...args) {console.log(args);} prints [].

Nothing makes any sense about this kata :\

It's solvable, an array of 2 words should be returned as specified. All the expects have custom messages, so under the condition that there's only 1 fixed test it's not an issue. A more general question is whether this testing format is acceptable at all. There's only 1 fixed test, so theoretically it can be solved manually and the answer can be hardcoded, although the input is large enough to discourage solving manually. I don't really like this, but I can't decide if it can be accepted as 8 kyu or not.

There is only one fixed test and the answer can be hard coded because there's only one answer. Most people who figured out the original puzzle on NPR probably didn't write a program to solve it...I did, so I turned it into a kata.

It's not conceptually different from asking, say, "what is the second prime number?".

I don't think that makes for a good kata. It's not that hard to generate random arrays that could be passed as an argument instead of the standard global variable, and turn this into a real programming exercise.