In unskilled hands, a chainsaw can be dangerous, it might even cut through an arm or a leg.
Ironically, that was what the first chainsaw was invented for.
A German named Bernard Heine (1800-1846) invented the chainsaw in 1830.
It was called an osteotome.
In those days before general anesthetics, surgeons depended on speed to shorten the suffering of patients.
The chainsaw was designed to speed up amputations by cutting through bone more quickly than was possible with conventional methods.
The device was operated by turning a crank manually, much like you would if you were using a hand mixer.
A Swiss German, Andreas Stihl (1896-1973), patented and developed an electric chainsaw for cutting wood in 1926.
Three years later he patented a gas-powered model.
Stihl is generally regarded as the father of the modem chainsaw.