"No you may not enchant an old ladys purse to gang up with other purses to beat her up" "fine what about her skin tags?"

No context needed 

HE GOT EATEN BY THE GIANT FISH HE USES AS A WEAPON

DON'T MAKE ME GO THROUGH MY THERAPY ARK AGAIN

I haven't been posting these lately so a few sessions' worth here...Tenth level party of Ferrin (half elf wizard/artificer), Sister Serena (aasimar cleric), Xanlar (half elf paladin), and Nu (axolotl shifter druid),  plus NPCs Phillip (human ranger), and Pin the kobold (rogue).

As the party returns to Phillip's squad, he is unhappy about  how we took their prisoner with us and then didn't come back with her because we made a deal with her to help our greater goals. Part of that deal is that that NPC will sabotage a heavily defended ship full of weapons in a nearby river port that Phillip is planning to attack. He doesn't believe us about much of it at all (Serena rolled a 1 for Persuasion to convince him we weren't crazy) and starts to lead his half dozen remaining able soldiers off to go carry out the raid. We don't want that because we've already made arrangements for that and it's also a borderline suicidal plan, so Ferrin upcasts hold person but one of Phillip's mages counterspells it and we're fighting, with the party attempting non-lethal methods but some of Phillip's soldiers not so much. Serena spends her first turn trying to persuade Phillip to calm down and again rolls poorly. 

DM: "Are you doing anything else?"
Serena: "No, I'm just yelling at my boyfriend right now."
DM: "Do you have a bonus action to do?"
Serena: "Just more yelling."
DM: "If it doesn't involve skill checks it's a free action. Girlfriends get that as a class ability."
Serena: "I'm yelling at him a lot."

Serena gets irritated at one of the casters...

Serena: "That's enough!" *casts guiding bolt, nat one for attack roll* "That was a warning shot!"
*Next turn another guiding bolt, this time a critical hit for 27 damage against the same caster*
Mage: "Aah! Holy $#@%!"
Serena: "I told you it was a warning shot!"

We manage to subdue them and everybody tries to calm down. After some tense discussions we come to an agreement to get along and abandon the plans for the raid. Phillip has a brief conversation with Ferrin...

Phillip: "I hope I'm the one that's wrong. Don't tell Serena."

Planning to try to outpace a large assault force headed downriver to attack an allied fortress. Our default method for such travel involves Nu's summoning abilities and after doing some math we settle on a bunch of giant bats to ride as mounts. One of Phillip's mages suggests we could get extra distance out of each flight period by letting the summons expire at high altitude and using feather fall to glide over the swampy jungle terrain a bit further. 

Serena: "Maybe we shouldn't make falling from hundreds of feet in the air Plan A."

During downtime on the trip, resting at the end of the day. Nu summons one of the largest creatures they can and states that they're going to play their magic flute repeatedly until getting the best possible buff effect and then storing it in said magic flute (this will allow them to summon it back later without needing concentration). 

Soldier: "What are you doing there, exactly?"
Nu: "I'm playing until he really really likes it! And then I'm gonna stuff 'im in the flute for later!"

Arriving at the fortress, which is garrisoned by a religious military order full of self important pretentious d-bags that Serena in particular doesn't like. 

Phillip: "Try to act smart and wise."
Serena: "I am always smart and wise."
Pin: "No you aren't."
Serena: "Like you're one to talk."
Pin: "I once saw her smash a bugbear's skull just out of nowhere."
Serena: "He had it coming."

After dealing with a pushy gate sergeant trying to be extra bossy by making demands beyond her authority just to push us around, we get into the fortress. After a moment we're greeted by an NPC named Jeferith, and elf woman we met briefly earlier. She starts acting very familiar and flirtatious with Phillip. 

Serena: "I'm just glaring at her with my arms crossed."
Nu: *muttering* "I am not looking forward to this."

The dwarven commander comes out, shirtless, accompanied by a drummer and a bunch of chanting. Phillip then briefly fistfights him as part of some sort of ritual and wins handily thanks to convenient dice rolls.

Serena: "Well that was anticlimactic."
Nu: "That guy kind of sucked."

The ensuing meeting does not go well, largely because the commander insists that his men simply cannot be defeated because they are blessed holy warriors. Nevermind that they have no siege weapons (those were sent away with another force to a different front) and the approaching force outnumbers them 4-1 and does have siege weapons. And the commander flat out states that 20 of his 50 troops are conscripts that he regards as useless weaklings and another ten he doesn't think very highly of either. But he adamantly insists that the gods are on his side so his twenty good men shall prevail against any odds without losing a single one of them. Serena thinks this is foolish hubris and eventually gets tired of hearing it so she responds with all of the tact and restraint to be expected from a stressed out and extremely frustrated teenager. Skipping to the point that we're getting kicked out of the meeting...

Nu: "Uh oh. We let Serena talk for too long."

Back on our own, brainstorming ideas to possibly delay or damage the enemy force which is still about two weeks away at their rate of approach.

Phillip: "Any ideas? Nu?"
Nu: *muttering* How many rhinos can I summon..."

"Klei looks down quickly and continues reducing the banana to banana dust."

Bard: Well we got everything we needed from the village.

DM: Okay, so will you continue to the hobgobli--

Silver dragonborn: WE SET THE VILLAGE ON FIRE

This was me in an adventure themed on the Hobbit:

DM: So you're in the wood elf village after escaping the deadly forest. What do you do?

Me: I LOOK FOR AN ELVEN BLACKSMITH WHO CAN GIVE ME A METAL BICUSPID

DM:...Why?

Me: What if I run out of weapons? It doubles as a dart, technically!

"I pretend I'm a gecko."

*rolls 22*

*Gecko Noises*

From a Holiday stream in a D&D-ish campaign (based on their D&D world, but in that world's future), they had an in-theme "A Christmas Carol" in their world setting. The 3rd deathly ghost with a huge bone scythe had threatened the primary NPC (Evan "The Geezer" Screws) that, if he didn't learn his lesson (you know the story), the ghost would return to slice him in half the following "Crimsnight" of the next year. After many attempts were made to make Screws mend his selfish, greedy ways—and it seemed to have finally worked (with the whole scene just like Scrooge realizing there was still time to celebrate Christmas in the original story), the stream ended with:

GM: Indeed, lessons were learned, wonderful times were had—
Player 2: —and we get paid.
GM: ...and you get paid, and in the end, Screws... also in a year... *rolls a die* ... ... 🤦🏻‍♂️
Player 2: ...gets sliced in half by a big bone scythe?
GM: ... Thanks for watching, everyone!

EDIT Trivia: Crimsnight is the eventual evolution of a yearly event from their medieval 5e campaigns called "All Crims Night" when an eccentric Lord would test his guards by letting criminals break into his castle to try to steal things. Crimsnight was a festive event where people would prank each other by trying to sneak into houses to purposely get caught with a festive, playful bonk on the head and well wishes. (Screws would mercilessly beat any intruding revelers to a pulp instead, totally against the Holiday tradition.)

Me: "Alright I punch the bartender in the face for trying to rip me off."

DM: Roll please.

Me: *Rolls a nat 20*

DM: You shatter his skull. Nobody wants to mess with you.

"I do a festive jig on the kobold's remains."

"I pee on the bugbears bed while he's asleep."

I've seen this happen a couple of times in streams:

*Player makes an awful pun*
DM: [Companion NPC] dies.

Quote from Theren_Dotsk >>

"I pee on the bugbears bed while he's asleep."

 Sneak Attack

I won’t put any actual quotes because it would be repetitive but: 

One of my players decided to ransack the desk of the director of an organization they were recruited to work at: it resulted in about a half an hour of wisdom saving throws with varied results. A majority of the times he ended up slamming against the wall and once even got thrown out of the room (because the drawers on the desk were enchanted to try and repel people who yknow, tried to ransack the desk). He was relatively successful finding: a cursed sword (which he does not know is cursed), a stack of letters (which he has yet to read), a stack of important looking documents (he also has yet to read those),  and various traditional fantasy office supplies. Also a stapler. Like. A modern day stapler (because I thought it was funny). He then ran to the quarters he shares with the rest of the party and stashed them under the bunk bed he shares with another one of the players (who has yet to find out). 

Needless to say that couple of sessions was. Something.

Edit: I accidentally typed “he also has yet to eat those” instead of “he also has yet to read those” somehow? That’s. Fixed now.

DM: "Everyone roll initiative."
Wizard: "Goodbye, everyone..."
DM: "Oh, oops! False alarm, everyone!"
Wizard: *sighs in a mix of relief and exasperation*

Rogue: "Can I steal [the paladin]'s crossbow?"
Paladin: "No."
Other DM: "Yes."
DM: "Make a Sleight of Hand check."
Rogue: "24!"
Paladin: "WHY?"
DM: "You succeed in taking [the paladin]'s crossbow."
Rogue: "Okay."
Other DM: "You can use your bonus action to shoot him with it."
Paladin: "Please don't."

Other DM (Pseudonymous_DnD): "Your javelin pierces the thing straight through the heart."
DM (me): "It doesn't have a heart."
Other DM: "Where its heart should be."
DM: "It hits it in the back."
Other DM: "Where you think its heart is."
DM: "...darn, I can't find anything wrong with that."

NPC: Come down here or die!

DM: You remember that that saying is a traditional greeting in Daruko-Iss.

Other DM (trying to find an in-game explanation for the absence of one player for one session): "Well of course! He's been...sleeping for the past ten days!"

DM: "Oh, guys, I'm so sorry about this...but...you...each take...eleven piercing damage!"
Wizard: "I have one hit point!!!"
DM: *proceeds to have a thirty-second fit of maniacal laughter*