Considering the temperature at which chocolate 'candy' is manufactured, it is highly improbable that a fly could plant viable eggs into the product prior to its being packaged.
Flies lay eggs into moist decaying 'food' or flesh so the larvae can survive when they hatch. Hard chocolate doen't fit the bill for fly larvae.
I have my cynical, disbelieving hat on for this one.
Believe it or not..this did used to happen when Reese's cups were packaged with paper.
If the bar had a toasted rice filling or other grain filling it could be weavil larvae.
Fly maggots are a long shot unless it was chocolate covered beef jerky but I've never tried that.
Yes...exactly what I think. Nice to see you support my theory. LOL. Its a Wendy's Finger attempt. Hope they get the same consequences.
This same thing happened to me with a Reese's Peanut Butter Cup that I had just purchased from the store.