the.com/wild card

The slot that lets nobodies storm the gates and occasionally burn the whole tournament down.

means A person or thing whose behavior or outcome can't be predicted, or an extra entry granted to someone who didn't qualify through the usual route.

from From the actual playing card — a card declared 'wild' in a game, free to stand in for any value its holder needs. That card-table sense, alive by the early 20th century in American English, spread outward: by mid-century it was leaping into sports (the unseeded entrant slipped into the bracket), then into computing (the 'wildcard character,' the * that matches anything), and into plain speech for any unpredictable element. 'Wild' here carries its old Germanic weight — untamed, ungoverned, out of the deck's lawful order.

sports origin
Lets non-qualifiers crash the postseason party
computing
The asterisk that means everything at once
super bowl glory
Wild card teams have won the whole thing
poker roots
Designated cards that can become any value
the idiom
Unpredictable element nobody can plan around
for instance

leicester city 2015-16 — won premier league at 5000-1 odds, first season outside top flight in 33 years

greece euro 2004 — 150-1 outsiders won european championship, defeated hosts portugal in final

the.com · every word