Out of thin air.
Get it running, just for fun, not actually recommended.
2D animation that remains ot top of every other open window. It requires a DE. Simple animations, like checking for the mouse o just randomly doing something. Not a pet, the idea is just to have it hovering the windows, period, no feeding, no walking, etc.
Keep the asset directory alive. I'm trying different sprites and I encourage you to do so, make your own, adapt an existing one, borrow, ask, do anything as long as you get your pet running all over your screen.