A woman had a "fright" after her six-year-old dog Otis found a scorpion running across the living room floor.
Karen Roberts, from Denbigh, said she was getting ready for bed when her Hungarian Vizsla became "very alert" to something on the floor.
"I was able to confine the little scorpion into a box with some sand, and he seemed quite content."
The creature, which is not dangerous and thought to be an escaped pet, has since been rehomed.
Ms Roberts said: "I sent photographs to my boss who is a geoscientist - who confirmed it was a scorpion, and was likely non-native.
"We contacted the RSPCA - and it was the first time both the call-handler and the officer had dealt with a scorpion call. It's great to hear the scorpion has settled into a safe new home."
RSPCA Cymru, who confirmed the scorpion was not injured, said the Euscorpius genus had been handed to a keeper who lives in the area.
It is unknown where the scorpion came from - but the RSPCA suspects it may be an escaped pet, or have returned amid somebody's holiday luggage.
However, there are also some small colonies living in the wild in the UK, it said.
RSPCA chief inspector Leanne Hardy said: "This must have come as a mighty surprise to this unsuspecting Denbigh family - after their dog spotted a scorpion casually strolling across the living room floor.
"Fortunately, the tiny scorpion was safe - and is now at appropriate facilities.
"This wasn't a dangerous species of scorpion - but we've no idea how he ended up house-visiting in Denbigh."