You have the power of reality.
When you are one of the main aliens in an encounter, your opponent's alien power is shut off when either alien initiates contact.
An abundance of sand coupled with low gravitation enabled the Martians to raise the art of 'kicking sand' to a galactic art form. Fully sentient for many Martian moons, the ethereal beings became increasingly annoyed at flybys, orbiters and probes poking about their dusty abode, where one rock too many was finally flipped. As if that were not intrusion enough, the Martians began picking up signals which seemed to indicate that scores of rival aliens were to be encountered in the immediate locale. Taking the opportunity for a brief sojourn to the offending location, they were quickly disabused of that notion. The spirited Martians instantly understood that they, and they alone, were the only 'real' aliens to be found. The simplicity of kicking sand in the faces of the 'so-called' alien powers masquerading as 'real' was so trivial as to be almost beneath their bother. Or so they thought.