If you don't know what a desktop pet is, then I'll try and break it down to the best of my ability without sounding like I've lost the plot. It's a virtual creature, or in this case, anime girl ...

If you've ever felt "my desktop background feels a little boring today," or, more specifically, "I'd like an anime girl on my desktop background," then VPet-Simulator has you covered.

The most recent addition to this roster is a Hatsune Miku DLC for Desktop Mate, a 'game' available on Steam that puts a sentient anime mascot (referred to as a desktop pet) on your screen.