The Rocket anvil is the Blob's anti air attack in C2: Judgement Clay. He starts out as a rocket, going upwards then slams into the ground as an anvil, making this attack hurt on the way down, too. This is a charge attack, meaning that you have to hold a directional button back, then press the opposite of that directional button and the button that requires the attack to work (along with the strength of the button). In this case, you have to hold down for at least two seconds, then press up and kick (any strength will do) to use the attack.