The most common and most likely answer to this crossword clue is the 8 plus 4 letter word MURPHY’S LAWÂ
I've seen this crossword clue in The Guardian
M
U
R
P
H
Y
â
€
™
S
L
A
W
Â
Buddy explains!

The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.