How do I use the "playerWhoClicked" parameter to find the player in the Workspace?

So basically I'm trying to make a button that makes the player who clicks it explode. When I tried using the "playerWhoClicked" parameter it returned the correct username. But when I try to use the username to find the player in the Workspace it doesn't work properly. An example of the code I'm using is at the bottom, I haven't put in the explosive stuff yet because I haven't gotten it to work.

local clicker = script.Parent.ClickDetector

function clickDetect(playerWhoClicked)
	local duckie = playerWhoClicked
	print(duckie)
	if game.Workspace:FindFirstChild(duckie) then
		print(":)") else
		print(":(")
	end
end

clicker.MouseClick:Connect(clickDetect)