The catchphrase of Taco Man, an unlikely superhero and the star cartoon character of Samuel T Nelson's Flash animation website Ebolaworld. Also the title of one Taco Man cartoon. It's like a cooler and detached yet sillier "d'oh!"
Taco Man: Now to save the kid!
(kid gets eaten by Donald McRonald)
Taco Man: Oopsidoodle!
when you're holding up your phone and making faces at it, as though you are taking a selfie, but you're really taking a picture of the person across from you or the wall or anything else that seems interesting but you don't want to be caught dead taking a picture of.
This action is often made more convincing by wiggling the eyebrows or opening the mouth, to pretend you're trying to get a Snapchat filter to work.