I know a word of letters three.
Add two more, and fewer there will be.
What word could this be?

Throw me off the highest building,
and I’ll not break.
But put me in the ocean, and I will.
What am I?

It’s true i bring serenity,
and hang around the stars,
but yet i live in misery,
you’ll find me behind bars.
With thieves and villains i consort,
in prison i’ll be found,
but i would never go to court,
unless there’s more than one.
Who am i? 

Though liquid to start,
don’t push me too far,
for then I will break,
and the damage may scar.
What am i?