How do you unlock varan?

Answer 1

You'll need to play story mode as an Alien. When in the level "The Mothership" you'll need to destroy these purple bunches of rock on the walls with your laser beam. After you destroy them complete the level. After the level there should be a level on the mothership that's called "Varan". Play the level and beat Varan and afterwards he should be available to buy at the store.