In that case let's try to get some good jumping legs and become tiny, jump at a bird and bring a mouth into existence. Store that bird and steal it's form.
Yeah, eat lizards and bats too. Then you can become a dragon.
Hey sure. Why not?Building a rather bottom heavy body structure, you try to get a set of legs that you can use to get some decent distance jumping. You end up with leg musculature that is easily the largest part of your body, but hey, whatever works right? With that bit of design accomplished, you begin to test out these new legs of yours, hopping up into the air... and immediately crashing into a wall. A second attempt fares little better, you manage to clear the wall, but sail through the air much farther than you intended, landing quite unceremoniously.
Shut up, this is harder than it looks. After an hour or so of practice, during which you frighten a mother and her pre-school child, you manage to get the hang of these legs enough that you can feel confident in being able to at least try to eat a grounded bird. With your eyes set on a magpie rooting through trash, you leap towards it, and forming a crude froglike mouth, gobble it in a single gulp, pushing it back into storage with the majority of your bulk to suffocate to death. From that point, it's not hard to steal a fairly close approximation of it's form, though considering your experiences with those legs you have doubts about mastering the creatures ability to fly before you damage the body enough that you would have to secure more materials.