The creature had been sliding across the metal bell plate, repeatedly setting off the buzzer and disturbing residents long after midnight. Initially, they suspected a klingelstreich – the German term for a doorbell prank in which children ring and run.

But the ringing continued even after police officers arrived. With no one visible at the door and the motion detector inactive, a closer inspection revealed the slug and its slime trail across the entry panel.

“We’d gone to bed … but we don’t tend to answer the door after 10pm, so when the bell rang, I tried to ignore it. I thought it might be the kids from over the road,” Lisa, 30, told Bild. “But then my sister-in-law, who lives upstairs, called and asked if our bell was ringing, as hers wouldn’t stop,” she added. They contacted police when the disturbance persisted “despite the fact no one could be seen at the door”.

A police spokesperson confirmed the intruder was removed and “taught about its territory boundaries” before being placed safely on a nearby patch of grass.