Here are some new tools to use in your "Creature" project...
Making Masks
You can make a mask from any active selection....
Here's the original image...
Let's take out the background...
THis is a good job for the "Quick select tool".... it picks up on the CONTRAST between background and the smoke...
Make a selection by click and drag over the smoke....
THink of PUSHING the selection into place with the tool..
Use the REFINE EDGE to improve the selection....
This is better...notice the slider for CONTRAST is moved...
Now I can convert the selection to a LAYER MASK...
The Mask hides the pixels, then I can paint on the mask to fine tune it if needed...
Choose the brush tool here...
Choose the size and blur of the brush with the control pannel..... or right click for it too!
Choose black or white to paint... Black HIDES and white REVEALS the pixels..
Be sure to have the mask selected- see the FRAME?