From Wiktionary, the free dictionary
this means war
- An avowal of anger towards someone, suggesting revenge is now sought.
1935, A Night at the Opera, spoken by Otis B. Driftwood (Groucho Marx):Of course, you know this means war!
1938, 6:20 from the start, in Porky's Hare Hunt, spoken by Rabbit (Mel Blanc):Of course, you know that this means war!
2024 February 26, Smii7Yplus, 21:26 from the start, in Worms Moments that End in Disaster[1], spoken by SMii7Y:This means war. This means war.