Most often occurs with:
Computers/ Technological Products, Cars, Mysterious Sounds etc.
Term is derived from the famous Looney Tunes short, "One Froggy Evening," in which a man finds a frog who routinely performs the song "The Michigan Rag" in front of him, yet remains silent and ordinary whenever he attempts to show him to anyone, driving him mad and resulting in his institutionalization.
Man walks into a car dealership after dropping his car off earlier that morning.
Man: So, did you figure out what the noise was?
Mechanic: Sir, there was no sound whatsoever.
Man: What?! What are you talking about, it keeps making this "SHHHISSHHHHARRRRERRRR" sound whenever it drives!
Mechanic: Yes... Of course it does, Sir..
Man: Ugh. I guess it's A Singing Frog.
Mechanic: (Raises eyebrows) What?
Dude 1: Dude. What is up with your computer screen? It's really fucked up. You should take it in.
Dude 2: Yeah but it only happens randomly. It'll probably not even act up when I take it in.
Dude 1: Ahh. It's A Singing Frog.
Dude 2: What? Shut up.
Dude 1: K...