Accurate Harkonnen Deathhand:

When you play as House Harkonnen, you receive a
palace in later levels. This palace contains the
Deathhand missile. While extremely powerful, it
is also the most highly inaccurate projectile. However, if you put the pointy end of your mouse on the top of a structure's flag when aiming and simultaneously hold down the letter T, this missile will destroy that structure and those around it in a single shot.