are they goo like? l mean,are changelings like clayface,where in their normal form they are gross,slimy goo like things that can make themselvs look like solid people? l ask cause l have a changling rouge and l was thinking: "could they fit into small gaps to escape?"  like turn into a goo like snake and slither inside pipes or go flat and go under door cracks?

They are humanoids with bones and meat and skin.

The have the ability to freely change the pigmentation of their skin and hair as well as adjust the shape of their muscles and skeletons. But they can never be anything other than a medium humanoid.

Think similar to Mystique (X-men)

Quote from Houligan >>

Think similar to Mystique (X-men)

 ah ok thanks.  are there any player race like l described? 

No, there aren't any ooze/slime type PC races, at least not officially.

There are no published (official) ooze based races.

The homebrew races have a variety of ooze based entries (seached for ooze in the name)

And insert shameless self-plug, one of those entries is mine: Ooze-Folk

Maybe a homebrewed playable Oblex race? :)