Cosmic Zap is an artifact that can be used to cancel one use of any alien's power and disable it for the rest of the encounter.
Notes from the FAQ
As noted in the FAQ for the FFG edition, a Cosmic Zap can also be used on a player who is attempting to use his or her super flare to prevent the use of the flare. A flare prevented this way is returned to its owner's hand and does not count against a player's one flare per encounter, and may be played later during the encounter for its Wild effect. This also cancels the corresponding alien's power for the rest of the encounter, as described above.
Other notes
Some cards, such as the Cosmic Field Generator tech card, state that using them counts as the use of a Cosmic Zap. This means that their effects follow the same rules as the Cosmic Zap (i.e. canceling an alien's power or super flare for one encounter) but are immune to the Card Zap because the player is not actually playing an artifact card in order to use these cards' effects.