Pipe Petard Achievement in Skylanders Giants
Chapter 11 - Damage Drill-X by throwing a pipe at him
How to unlock Pipe Petard
Drill-X is the boss of Chapter 11. There will be two pipes sticking out of the ground, which you can use as cover during the fight. At the start of the fight, switch to a Giant Skylander, and pull one of them out of the ground and toss it at Drill-X's drill when it gets stuck in the ground. Make sure to do this in the beginning of the battle, as the pipes will get destroyed during the fight requiring a replay if you don't get it.