You know what the Mojave desert was missing? My Little Pony, of course. My Little Pony buddies, to be precise. Here's a mod by Kuroitsune and Riven1978 on New Vegas Nexus that allows you to have the MLP protagonists as your companions. Not all ponies are included—for now, there's only Luna, Celestia, Twilight, Fluttershy, Applejack, Rarity, Rainbow Dash, Pinkie Pie, Ditzy/Derpy and a few others. Perhaps the best part about this is that the ponies come with specific perks.
Littlepip - Stable 2 - Whenever Littlepip is your Pony Companion, you will receive +10 points to Science, Medicine, and Repair and 1 point to Charisma, at a cost of 1 point of Agility and Strength, and -5 to Guns, Melee Weapons, and Unarmed Weapons.
Luna - Mare of the Moon - During the night as long as Luna is your Pony Companion, you will slowly regenerate health. Luna will also gain a 20% combat effectiveness.
Celestia - Mare of the Sun - During the day as long as Celestia is your Pony Companion, you will receive 30 points to Energy Weapons, at a cost of 10 to all of your other offensive skills. Celestia also gains a 20% damage potential.
BonBon - Friendship Is Magic - When Bon Bon's health gets below 30%, Lyra will appear to help out in the battle.
Lyra - Friendship Is Magic - When Lyra's health gets below 30%, Bon Bon will appear to help out in the battle.
Twilight - Studious - Twilight's intelligence is par none. While she is your Pony Companion, your accuracy, spread, and critical chance improve by 20%.
Fluttershy - All Creatures Great and Small - While Fluttershy is your Pony Companion, every creature in the Mojave is your friend, at the cost of your human relationships.
AppleJack - Apple Cider - While Applejack is your Pony Companion, she will give you Apple Cider every time you give her 2 Apples.
Rarity - Rarity & Charity - While Rarity is your Pony Companion, you will find more caps or hard to find weapons on fallen foes only she kills.
Rainbow Dash - Speedy Arrival - While Rainbow Dash is your Pony Companion, you will be 10% faster at everything you do, at the cost of 30lbs of your total carry weight.
Pinkie Pie - Party Time! - While Pinkie Pie is your Pony Companion, you will find more chems on your fallen enemies. But you will be 20% more likely to become addicted to chems.
Derpy - Muffins! - While Derpy is your Pony Companion, she will give you 3 Muffins every time you use a campfire once a day.
Trixie - Trixie's Greatness - While Trixie is your Pony Companion, you gain +10 to all of your skills that are under 50 skill points.
Vinyl Scratch - Bass Cannon - Whenever Vinyl Scratch is your Pony Companion, any explosive based weapon you use will have three times the power, at a cost of -20 of your sneak skill.
You can download it here, though I'm a little sad that they walk upright. I mean, that kind of makes it more hilarious, but still!
My Little Pony Follower [New Vegas]