Is your feature request related to a problem? Please describe.
No. It's a new effect request.

Describe the solution you'd like
The twinklecat effect is very nice, and I noticed in the code that it is a simple adjustment on the twinklefox effect.
The effect that I would like to see is the opposite of the twinklecat (twinkledog maybe?) where the twinkling lights fade from the background to the selected color or palette segment, and then once max brightness is reached, instantly go back to background color.

I imagine this would look really cool with a bright background and a dark foreground colors.

Describe alternatives you've considered
No alternatives exist.

This is probably a really easy fix, and I saw the location in the code where it would be possible to just add it myself, but my C++ is very sad, and I'm not exactly sure what all the variables are doing. Particularly, the ph var that looks like it drives the whole thing.