As we've established, we're big fans of RPG game. These aren't just any rats, mind you – they come in a wide variety of exotic patterns.
The Scrolls for Rats Companions mod by gg77 adds a whole rainbow of potential giant rat companions to Skyrim. These designer rats come in a surprisingly diverse range of colourations and patterns: in addition to your standard white and black rats, there are tiger-striped rats, zebra rats, and ocelot rats. However, they only come in one size: large.
Once you've installed the mod, you can acquire your rat companion by visiting Whiterun and buying a special rat scroll from Hulda at the Bannered Mare or Belethor at the General Goods store. Find the scroll in your inventory, toss it at the ground, and poof! Your rat will have appeared, ready to follow you into the deepest tombs and highest mountain peaks in Skyrim.
Sadly, you still can only have one giant rat companion at a time. You'll have to dismiss your current rat before you can try out a new one with a different fur pattern.
If you've been experimenting with the Immersive Rejections mod and need a companion who will never shoot you down, these giant rats may be just what the doctor ordered.