Do you know any cool biological traits an alien could have?

Depends what sort of environment they evolved in, and whether anybody (themselves or another species) has decided to modify them since.

A long tongue is useful for an animal like a frog or a chameleon, that sits motionless and waits for food to come within reach. It's not so useful for, say, a lion, that chases prey and brings it down with teeth and claws. 360-degree vision is useful if something might try to sneak up on you and you're not strong enough to win a fight. It's not so good if you're the one doing the sneaking, and you need to judge distances to know whether you're in range to jump at your target. Herbivores tend to have eyes on the sides of their heads, to be able to spot predators from as many directions as possible. Carnivores tend to have eyes in the front of their heads, the better to judge distances and build an accurate mental map of the best route to sneak up on their prey.

Serious answer: 360 degree vision (eyes in the back of the head).

It's realistic, pro-survival, and fits in with an "evolution by natural selection" model.

Considering we don't know of any aliens to study the biology of, why don't you use your brain (LE GASP!) and think of some.

The females would have the ability to wrap their legs around my torso like Elasti-Girl from The Incredibles.

ability to shapeshift into anything in our nature