Toys making noise when nobody is around to play with them is a pretty common “ghost” encounter. We had one ourselves with a Sesame Street Ernie doll that would randomly say “I feel great” in an empty room , in the middle of the night, etc. caught it on video once triggering with the doll just lying on the floor.

Turns out when battery voltage gets low (but not yet dead) this can happen in a circuit. I swapped out the batteries and our ghost never came back. Not surprised to hear it happening in a store where stock just sits there for a long time.

Pretty creepy though to hear that when you are lying in bed

I was in the house a couple of weeks ago when I kept hearing a voice coming from upstairs every so often I couldn't track down because it never happened when I was up there.

I had forgotten my son bought the Nintendo Talking Flower: https://www.nintendo.com/au/products/talking-flower/ Usually his door is closed when he leaves but that day it had been left open.

Which is to say, nowadays we have some toys that spontaneously speak in the middle of the day with no input too, by design. It didn't "freak me out" or anything, it was clearly an electronic sound from a speaker. Did make me ponder the idea of leaving some sort of speaker with a software-defined-radio wired into the mains so I could do a drive by of my old house a few years later and start transmitting things into it around Halloween or something, though.

The best part is those older toys with low batteries would have an extra creep to the voice because of the low voltage. We had one that sounded absolutely possessed by a devil. It was truly terrifying to hear that in the middle of the night :-D

One of my son's old toys is up in some box in the attic. Whenever I go up there, about one in three times it says, "The lions says 'Roar'", when I'm walking back down the attic stairs. I don't know why that is what trips it, as walking up them doesn't seem to, and I don't know what box it is in and can't be bothered to look for it the pull the batteries out. It's been doing that for years, as he's in college now.

If I manufactured toys I'd definitely make 1 in 10,000 toys randomly go off just to mess with people.

I had something similar happen to me as a kid with a furby, as if they weren't creepy enough normally.

Wow, nostalgia. I have heard that same "I feel great" Ernie line a thousand times.