I noticed small repetitive movements, almost as if the "thing" was trying to escape the plastic packaging.
Closer examination revealed the truth to me
It turned out to be a small, harmless snake. The shock was great. You never expect to find anything but fruit in a sealed package, but here it was.
This discovery made me think about the need to be more careful with what we eat. The strawberries looked flawless: red, shiny, completely clean. Nothing suggested that such an unwanted "guest" was hiding inside them.