In the costume editor, you should be able to draw effects like with the

change [ v] effect by (25)

block.
So, if you chose “ghost”, there would be a slider to set it from 1 to 100 to select the effectiveness of the effect, and drawing with it would give the area you draw the ghost effect. You can also use the fill tool, circle tool, etc. to draw with the effect.

It could be used for making only part of a sprite transparent, making windows in a game, etc.

It's kind of hard to explain everything about this.

I don't see a need for mosaic, fisheye, and whirl as brushes, but the rest seem pretty helpful. (especially ghost!)

fdreerf wrote:

I don't see a need for mosaic, fisheye, and whirl as brushes, but the rest seem pretty helpful. (especially ghost!)

i wonder if color could work? i'm not sure how it would work though