Parents across the world have been left outraged after a children's application downloaded from Google's official marketplace contained threatening and violent messages.

Uploaded under the name "call Blaze and the Monster Machines 2018" – but unaffiliated with the Nickelodeon animated series – the app was disguised as way to let children talk to their favourite cartoon character. In reality, a menacing recording talked about stabbing the listener.

Reports in the UK and Australia detailed the accounts of horrified parents who exposed the app as a danger to children and got it taken offline.

Footage of the recording was published by the Manchester Evening News Tuesday (23 January).

It showed the app stating: "Hi kids, I'm your new friend Happy Slappy, whatever you want me to be called. You see I want to play with you kiddo, maybe we could perform some fun games together.

"What's this hogwash? You look afraid," it continued. "Is it this knife in my whirly twirly hands? Making you a little nervous ha? That's all right 'cause this knife is gonna improve your look when it's sticking right out of you."

Before being taken offline, the ad-ridden app had racked up more than 1,000 downloads.

Yahoo Australia reported that its developer – using the name 'Ralph dev1' – had uploaded more than 40 apps in total, mimicking popular characters including Tom and Jerry, Iron Man and Mario.

One concerned mother, 25-year-old Lucinda Short, told Yahoo Australia : "I was just browsing through the apps and came across it. I later saw that people were posting about it online.

"I think some parents would recognise the character and download it for their kids to play on without realising what was on it. Luckily I didn't play it to my daughter or two nephews."

She added: "If the kid had heard this, they wouldn't sleep for weeks I've honestly no idea why anyone would want to do this – maybe they just want to scare kids on purpose. It's really disturbing that people are creating this kind of thing and threatening to stab young children."

A Google spokesperson said: "We have a set of policies designed to provide a great experience for users and developers and we act quickly to remove apps from Google Play that violate those policies."

Tony Stower, head of safety at UK children's charity, the NSPCC, said that parents needed to have "regular conversations with their children about staying safe online".