Picture sourc: unveiling-christianity.net
That has got to be the prophet Isaiah. It was in response to an instruction from God. It was to this be a sign from God.
The thing is that the old testament is in types and shadows. Everything you see has an underlying meaning.
The prophet was asked to do this too show that destruction was coming to the Egyptians and Asyrians who were against God's people. It was to show that they were naked before God's and could not hidden from His presence.
It's the same way Hosea was asked to marry an harlot to show that Israel had been practising stuffs that could be related to adultery.