Fionn mac Cumhaill, also known as Finn McCool, is an Irish mythical giant of immense muscle and might. Like other legendary men of enormous size and great strength, he is credited with shaping the landscape. Fionn mac Cumhaill is said to have created Giants Causeway, Loch Neagh and the Isle of Man. Here's how the legends go. Enraged by Benandonner, a Scottish rival, Fionn mac Cumhaill threw rocks from Ireland to Scotland so he could step across the sea and battle his enemy. The result was Giants Causeway. In another fight with a foe, Fionn mac Cumhaill picked up a fistful of earth and hurled it across the sea towards England. The hole left by the soil filled with water and formed Loch Neagh. The fistful of earth missed its target and fell into the Irish Sea creating the Isle of Man.