From a series of gameplay guns I had sketched out last year.
I always like novel ideas that let you interact with the artificial world you get to play in.
Interesting to see how you could mod these to get them to break physics and do more interesting behaviours than the more obvious.
But ideas are hard to sell without showing the more obvious ways it could be fun.
In any case just testing out Blender 2.8 with some hard surface work.