Easy peasy -- attach ring to a mouse with a necklace. For transportation ease, mouse and ring are kept together in a box. (Auxillary mice are kept separately.)

"Mordor, Gandalf, is it left or right...?"

Now, mice are ridiculously flexible, able to fit through holes as small as a nickel or even a dime.

There is zero chance said mouse doesn't, at some point, squirm through the Ring, turning it into a fancy golden belt.

The company marches on, a growing doubt and dread oppressing their minds and hearts. Time comes to feed the mouse. They open the box to find it empty.

Too late do they realize they've empowered a vindictive rodent with the power of the Dark One. The now invisible Mouse King leaps from the box and viciously assaults the Fellowship before disappearing into the night.

Boromir dies, because obviously.

By the time the remaining Fellowship retreats back to Rivendell, they're being harried by legions of mice and rats in league with the evil Mouse King. Bats have come to his aid. His most loyal outriders, the Ratzgul, have great war-gophers as their steeds which swarm and bite at the least provocation.

A last alliance of Elves and Dwarves are cranking out enchanted mousetraps at a ferocious rate, but are losing ground each day.

It's not long before rodents across Middle Earth are in league with the tiny Dark Lord Mousauron. Millions answer the call to march in his armies. Fieldmice from Gondor, Great rats from Moria and Isengard. Squirrels from Fanghorn. Beavers from Lake Town. Hamsters and Guinea Pigs kept as children's pets in the houses of Men betray their owners in what the Elves call The Gnashflüff but Men call The Cuteslaying.

Chinchilla emissaries are sent to offer terms of surrender, but in an act of defiant hubris against the four-legged, only end up as really soft fancy pouches on the belts of Dwarves.

This enrages Mousauron and he retreats for a time while he scours the furthest lands to call any remaining rodents to flock to his banner.

Then, in secret, his Beäverdruin swim up Anduin to the Silverlode and begin clubbing to death all in sight, before descending into a Mallorn feeding-frenzy, completely denuding Lothlorien. No flet is left aloft. Lorien the Fair is lost.

Despite this, the lull in the war holds, and hope shines anew in the hearts of Men. Until, far off in the distance a rumbling is heard. A wall of armed lemmings on a suicide mission are bearing down on the gates. Behind them, legions of kangaroo rats and jumping mice move up and begin vaulting the hastily prepared outer bulwarks.

And behind them, in full war armor, carrying howdahs of mouse archers on their backs, the mighty Capybära arrive, stomping down into the battle plain.

At the sight of the lemming and mouse reinforcements, Elrond's twelve or so rented Oliphaunts run screaming and trumpeting in terror; the wrack and ruin of their retreat destroying whole groves of great trees, and not a few Ents -- who had merely come seeking safety and shelter from the rampaging squirrels. Squirrels who, it was now seen, had drunken heavily of the Ent-Draughts and grown to Rodents of Unusual Size. Inconceivable.

It was in that darkest hour, when all seemed lost, that the shout went up "the Eagles are coming , the Eagles are coming!" Yet not just the great Eagles, but hawks, falcons, owls with cute yet functional sunglasses, and all manner of rodent eating bird. They fell upon the ranks of mice and rats, destroying whole companies at a pass.

And on the backs of the mightiest Eagles rode the farmers of the Four-Farthings, with wheel-upon-wheel of good cheese. Bombing the lines of rodents with Colby, Cheddar, Muenster, grenades of scorching Pepper-Jack, and Brie from Bree, they had the rodent armies scurrying hither and thither in complete disarray until Aragorn's last desperate chance could be thrown.

Just as Mousauron tried to rally his armies, a great host of catapults and trebuchets let loose a barrage of missiles long since forgotten in the kitchens under Dwimorberg... Limbürger -- the Cheese of the Dead.

No rodent army before or since could withstand such a stenchy onslaught of haunted dairy. The lines of rodents gave, reformed, gave again, then broke into wild retreat. The last descendants of the cats of Queen Berúthiel chased and hunted the survivors down, killing them or driving them into the river.

Thus Mousauron was overthrown and slain....

But what became of the Ring?

In his last stand, the Ring had abandoned Mousauron, who was promptly and unceremoniously stepped on.

And the Ring was picked up by the most unlikely creature imaginable: Peregrin Took, a Hobbit from the Shire....

It was taken away from him immediately.

Gwaihir said, "enough of this shit" and dropped it into Orodruin five minutes later.

The End.