Peyton Manning must've missed a production meeting ... 'cause the Hall of Famer looked absolutely shocked beyond belief when Arnold Schwarzenegger fed his pet donkey, Lulu, in front of millions during MNF, and the legendary signal caller's reaction was priceless!
The awkward moment went down during Peyton and brother Eli Manning's 'Manningcast' show on ESPN during the NY Jets vs. L.A. Chargers game Monday night.
As always, the famous football bros brought A-list guests to the show ... this time bringing on the one and only Arnold.