Initially thinking it was a Halloween toy, he was horrified when he realised that the animal was real, according to Metro.
The incident was reported to health officials, who believe the bat may have flown into the plastic packaging by mistake and suffocated to death.
Food safety official Jorg Sturmer said: "I have never seen anything like it. This really is an unusual case."
Scientists are now investigating whether the animal found in the box of Mini Zimties got in in the factory or after the packet was opened at the man's home in Stuttgart.
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