A Slice of Life is a comic My Little Pony: Friendship Is Magic fanfic.Life is easy for Princess Celestia... too easy, she feels. She wishes something would go wrong just to relieve the tedium of dealing with snooty nobles, boring bureaucrats, and the Equestrian Tax Structure. Unfortunately, she's about to get her wish. Seems her solar majesty has put on a few pounds, so it's time for the Royal Diet... and all of Equestria may not survive.
Adipose Rex: After Nightmare Moon's banishment one thousand years ago, Celestia admits that she "may have let herself go a little" during that time. One period of time during this was even named "The Great Decade of Cheesecake".
Feather Duster: They had to cart her to her throne in a wheel barrow.
Brick Joke: A bill proposing an anti-ninja-zombie contingency plans in hospitals. Dismissed by Celestia as ridiculous in Chapter 3; after a swarm of them attacks a hospital in Chapter 10, she hastily approves the bill while preparing to invade the castle kitchens.
The Chessmaster: In Chapter 10, it turns out that Princess Celestia enlisted a band of retired soldiers who are loyal to her but not bound by their oath to help her stick to her diet, wore out (nearly) all the members of the Royal Guard by holding a late-night dance party, and sent both Feather Duster and Luna away, all so she could sneak a snack from the kitchen. To drive the point home, Private Hoplite recalls getting his rump kicked the first and only time he played chess with Celestia.
Combat Pragmatist: Lethe. She often fakes being injured and playing up the Puppy-Dog Eyes to get opponents to drop their guard, before attacking suddenly. In one case, she faked dislocating her wing to get a mercenary to drop his water baloon, and then slammed two pies into his head after he helped her up.
Death World: The province of Oxtria is as bad as Australia. It was where Chernobull exploded, leading to sea bass that are worse than piranhas with metal dentures, and irradiated hay that attacks you.
Celestia decided that if she could get away with it this year, she would try to embezzle funds from the Grand Galloping Gala budget in favour of a construction project. After all, what pony in their right mind would waste bits on diamond encrusted napkins when they could be used to build a nice, thick wall around the province of Oxtria?
Dogged Nice Guy: Sergeant Hoplite has a crush on Princess Celestia, fantasizing about taking her on a date the Grand Galloping Gala and proposing to her. Since we know Celestia's point of view, we know that she barely gives him a thought apart from "that guardspony."
Food Fight: Most "warfare" has been reduced to this, and Equestria and Griffonia have many mock battles in this fashion. Water balloons and pillows become ammunition as well.
Also, when Celestia and her private army raid the Royal Kitchen, the fight between her soldier and the cooking staff goes this way.
Hidden Depths: Apparently, when he's not working out like crazy, Schwarzwälder enjoys gardening. Though in his case, he had trouble with last year's harvest because the cauliflower he imported from his homeland ate his chainsaw.
Private Lethe may be excessively unrefined, unprofessional in her line of work, and joined the Night Guard because "she'd look cooler," but she was able to give a well-planned response plan to the hypothetical resurgence of an obscure ancient evil. Then again, considering her Night Guard duties, this may be expected.
Hollywood Pudgy: Invoked and Lampshaded when Luna points out Celestia's extra weight doesn't really show, and she expresses concern that they're taking the "Royal Diet" thing too far.
"Protect the cheesecake! Protect it with your life!"
Comes to a head starting with chapter 10, when Celestia prepares to not just raid the royal kitchens, but lay siege to them. In chapter 11, we find Celestia completely rewriting Equestria's laws so she can get away with it, too.
Red Shirt Army: In Chapter 9, Lethe tries to get Hoplite to stop taking his job too seriously by pointing out that the guards weren't exactly useful during the return of Nightmare Moon or the revival of Discord.
Ring Ring Crunch: Happens several times, with increasing force as Celestia gets more frustrated with her diet.
Shamu Fu: Ram Sea uses a swordfish as an improvised weapon.
Skewed Priorities: In order to gain a private army to raid the Royal Kitchens, Celestia agrees to sign many legislative bills for the ponies' support. She eventually stops skimming the titles and just starts signing the dotted lines, so she could have just signed Equestria over to her secretary for all she noticed.
There Was a Door: In Chapter 11, Luna leaves the Haunches gym by smashing through the ceiling, though she was courteous enough to leave a bag of bits to pay for the repairs first.
Training from Hell: Poor Celestia's exercise routine. Her personal trainer, Schwarzwälder, does this intentionally, since Celestia is a Physical God, he seems to think that she can handle literally anything he can throw at her.