ARGENTINE TOWNSHIP, Mich. (AP) — Two girls have found what authorities say is a World War I-era practice bomb while swimming in a lake in Michigan.

The Flint Journal reports that 10-year-old Paige Burnett and 9-year-old Sage Menzies were searching for items below the surface of Lobdell Lake, recently, when Paige felt something unusual.

The girls and Sage’s mother dragged the 3-foot-long mystery find from the murky water. Paige says they were excited at first, but then got worried. She says she was “so scared” it might explode.

The lake is in Genesee County’s Argentine Township, about 45 miles northwest of Detroit. Township police Sgt. Douglas Fulton says the Michigan State Police’s bomb squad came out and drilled a hole in it, but “nothing but mud came out.”

In this Wednesday, May 30, 2018 photo, Paige Burnett, 10, left, and Sage Menzies, 9 pose with a World War I practice bomb they discovered the day before while swimming in Lobdell Lake behind the Menzies’ home in Linden, Mich. The two found the bomb while pretending to be mermaids, and diving deep to search through the mucky lake bottom, when they found the tail end of the practice bomb. (Jake May/The Flint Journal via AP)

http://www.sidneydailynews.com/wp-content/uploads/sites/47/2018/06/web1_120671234-cb6a4d67340e43aea99bf6dc42128869.jpgIn this Wednesday, May 30, 2018 photo, Paige Burnett, 10, left, and Sage Menzies, 9 pose with a World War I practice bomb they discovered the day before while swimming in Lobdell Lake behind the Menzies’ home in Linden, Mich. The two found the bomb while pretending to be mermaids, and diving deep to search through the mucky lake bottom, when they found the tail end of the practice bomb. (Jake May/The Flint Journal via AP)

In this Wednesday, May 30, 2018 photo, Paige Burnett, 10, left, and Sage Menzies, 9 pose with a World War I practice bomb they discovered the day before while swimming in Lobdell Lake behind the Menzies’ home in Linden, Mich. The two found the bomb while pretending to be mermaids, and diving deep to search through the mucky lake bottom, when they found the tail end of the practice bomb. (Jake May/The Flint Journal via AP)

http://www.sidneydailynews.com/wp-content/uploads/sites/47/2018/06/web1_120671234-6edeb7814fc34fd79bdb9507ea7a7e63.jpgIn this Wednesday, May 30, 2018 photo, Paige Burnett, 10, left, and Sage Menzies, 9 pose with a World War I practice bomb they discovered the day before while swimming in Lobdell Lake behind the Menzies’ home in Linden, Mich. The two found the bomb while pretending to be mermaids, and diving deep to search through the mucky lake bottom, when they found the tail end of the practice bomb. (Jake May/The Flint Journal via AP)

In this Wednesday, May 30, 2018 photo, a heavily worn World War I practice bomb rests on the ground the day after Paige Burnett, 10, and Sage Menzies, 9, discovered it while swimming in Lobdell Lake behind the Menzies’ home in Linden, Mich. The two found the bomb while pretending to be mermaids, and diving deep to search through the mucky lake bottom, when they found the tail end of the practice bomb. (Jake May/The Flint Journal via AP)

http://www.sidneydailynews.com/wp-content/uploads/sites/47/2018/06/web1_120671234-3c80f78d835647aaa98e88dc85b54cf0.jpgIn this Wednesday, May 30, 2018 photo, a heavily worn World War I practice bomb rests on the ground the day after Paige Burnett, 10, and Sage Menzies, 9, discovered it while swimming in Lobdell Lake behind the Menzies’ home in Linden, Mich. The two found the bomb while pretending to be mermaids, and diving deep to search through the mucky lake bottom, when they found the tail end of the practice bomb. (Jake May/The Flint Journal via AP)