HitchBOT, a friendly hitchhiking robot that became famous on social media during its travels through Canada and Europe has been destroyed while on a trip across the United States.

“Unfortunately, hitchBOT was vandalized overnight in Philadelphia,” the robot’s creators said in a statement on Saturday. “Sometimes bad things happen to good robots.”

HitchBOT was designed by a team of Canadian researchers as a social experiment to explore the relationship between humans and technology.

McMaster University's David Smith and Ryerson University's Frauke Zeller said they created the robot in an attempt to answer the questions: “Can we trust robots?” and “Can robots trust human beings?”

Smith and Zeller would soon find out.

In 2014, hitchBOT set out from Halifax on a cross-Canada tour that ended in Victoria, B.C. Though there were fears hitchBOT would be destroyed or kidnapped along its unaccompanied trek, the robot reached the West Coast relatively unscathed, thanks to the kindness of strangers who provided rides and sometimes, lodging.

Apart from a tune-up in Toronto and a small crack in the clear plastic part of its head, no medical care was required.

The robot couldn’t move by itself, with the exception of its hitchhiking arm and finger, and was therefore dependent on the goodwill of strangers, Zeller told CTV News Channel in 2014 interview.

Designed to be a talking travel companion, hitchBOT could toss out factoids and carry limited conversation. The robot would automatically snap a photo every 20 minutes to document its travels.

The robot proved quite popular, with dozens of photos of people posing with the robot emerging on social media.

After successfully travelling across Canada and parts of Europe, the robot set off on a tour of the U.S. in mid-July, visiting a variety of sites in Massachusetts and New York before meeting its demise in Philadelphia.

The researchers were sent a photo of the damaged robot, but have been unable to work out its location because its battery is dead.

It is still unclear who destroyed hitchBOT or why, its creators told The Associated Press Saturday.

During past travels, the robot attended a comic convention and a wedding, and it had its portrait painted in the Netherlands. It once spent a week with a heavy metal band.

With files from The Associated Press