God said to Moses and Aaron, "Take fistfuls of soot from a furnace and have Moses throw it into the air right before Pharaoh's eyes;
it will become a film of fine dust all over Egypt and cause sores, an eruption of boils on people and animals throughout Egypt."
So they took soot from a furnace, stood in front of Pharaoh, and threw it up into the air. It caused boils to erupt on people and animals.
The magicians weren't able to compete with Moses this time because of the boils - they were covered with boils just like everyone else in Egypt.
God hardened Pharaoh in his stubbornness. He wouldn't listen, just as God had said to Moses. Strike Seven: Hail