The numerous Groo series contain examples of the following tropes:
Abandon Ship: Almost always happens whenever Groo gets on board a boat.
His ability to sink ships actually been exaggerated over time. Originally he would often do something idiotic, like take wood from the bottom of the ship to fix a hole in the side. Eventually it got to the point as soon as he steps on board the the ship spontaneously springs a leak and goes to the bottom of the sea. The only way he can safely board a ship now is when he is with Rufferto.
Attending Your Own Funeral: Done for drama in "The Death of Groo" graphic novel. Groo goes to his own funeral expecting there to be much sadness at his demise. There isn't; everybody at that funeral had endless trouble from him, and they were all delighted at his "death."
Grooella: "Today I have become something I have always wanted to be... an only child!"
Baleful Polymorph: Witch and wizards in Groo's world enjoy doing this to their enemies sometimes if really angry they will transform into the most horrible thing they can think of... Groo! Sadly, having multiple Groos bumbling about usually results in even greater catastrophe.
Barbarian Longhair: The title character is a barbarian with long hair. He is very stupid and exceptionally skilled with the sword.
Berserk Button: Groo is not a mendicant. Started in the second issue ever, where it was kind of justified because he had just lost all his money, and continued for years even some time after he learned to read and found out what it meant.
Big, Thin, Short Trio: Pipil Khan's three sons, a large, burly warrior, a powerful magician, and the scheming, weasly runt of the family.
"I will mulch you!" Mark Evanier lamented that he should've known after getting mailed cheese dip by hundreds of fans every month what this catch phrase would lead to...
That is one of many ways the word was used. The tradition started with a story where Groo wandered into a village where all the women had been abducted by Sky Pirates. Any mention of what the women were needed for made the villagers list several tasks, always ending with a reference to mulching (some times accompanied by a shoveling motion). A number of readers asked what the word meant, and in the next issue the editor filled the letter column with their notes and his answers - which all consisted of the dictionary definition of the term. The rest is history.
The phrase also crept into other comics, such as Usagi Yojimbo (including an overexpository "I will cut you into fertilizer or mulch!")
"Mulch" was also revealed to be the name of the Sage's dog — at the end of a Running Gag where everyone who mentioned the Sage in any context would also mention his dog ... and then be interrupted or interrupt himself with the question, "Say, what's that dog's name, anyway?"
Doom Magnet: There are a few, a few, people who haven't suffered from being in the same general area as Groo:
Just about everyone who really suffers from encountering Groo deserves it to some degree, And those few people who look beyond Groo's faults and show true heart and/or kindness are generally better off for having met him.. even if it's generally by accident.
Mark Evanier played around with this in a letters column when a reader asked if Groo would ever team up with any Marvel characters. Evanier said that the reason that Groo did not end up meeting Wolverine, for instance is that it would be a very short issue — Panel 1: Groo and Wolverine meet. Panel 2: Groo kills Wolverine. Panels 3-88 are blank. End of story.note The genuine reason is that Groo had zero to do with Marvel continuity other than being published by Marvel's creator-owned Epic imprint at the time — the character was owned lock, stock and barrel by Sergio Aragonès (the reason he did not publish Groo for years was that he wanted complete creative control and ownership and had been told by the Bigs that it just wasn't done in the industry, until Pacific Comics offered him just that.)
He once did once help a free a group of slaves by exposing veins of gems by causing a block of rock the were excavating to fall off and shatter. But as the slaves came to thank Groo, he thought that they were chasing him off (again). Groo ran away without ever learning the truth.
Easy Amnesia: Taken to its logical extreme in a story where some characters need Groo to keep his memory while others need him to forget. They literally turns Groo's memory on and off by hitting him repeatedly on the head.
Eat the Dog: Subverted; when Groo first meets Rufferto, Rufferto thinks he's found a caring new master, but what he sees as Groo's affection is really just hunger. Soon afterward Groo thinks he has eaten Rufferto and becomes overwhelmed with guilt. When Rufferto finally shows up alive and well, Groo genuinely become a caring master.
Elephants' Graveyard: An early comic plays this for laughs, with Groo following a wheezing, doddery old elephant in the hope of a meal, and finding a huge field of elephant bones. Groo is excited at finding tons of ivory, but his celebration is cut short when the dying elephant falls on him.
The End... Or Is It?: In "The Aranja", Groo and Chakaal are hired to kill a giant spider that is terrorizing a village. Stumbling drunkenly around the spider's cave, Groo notices something he figures is important and tries to tell Chakaal, who is unfortunately too busy to listen. Soon after, Groo has forgotten the whole thing. As the heroes depart at the end of the story, the readers are shown what Groo discovered: The aranja was a female, and it had laid several eggs, which are just starting to hatch.
Exact Words: In one issue, Groo is hired by a kingdom at war to "guard this bridge" against an invading army. Groo takes up his position before the bridge, and the army approaches slowly, seeing Groo there. They cross the bridge under his watchful eyes unmolested. After the invaders overthrow the kingdom, the fleeing King demands of Groo why he didn't guard the bridge, Groo is confused:
Groo: But I did guard the bridge! No one damaged the bridge! No one stole the bridge! No one soiled the bridge! When Groo guards a bridge, Groo guards a bridge!
Expressive Accessory: The head of the Minstrel's lute changes into a different object in every panel.
The Fool: Groo is probably the biggest example of them all. Barely capable of feeding himself, Groo brings bad luck wherever he goes and has a bad habit of decimating whole towns and cities, often as a result of trying to help the local residents. Nearly every comic ends with him being chased by an angry mob while he tries to figure out why.
Getting Crap Past the Radar: One early comic involves Groo being forced to disguise himself as a harem slave to sneak inside a highly guarded palace to steal a ruby, and the woman helping him with the disguise instructs him to move his hips more feminine. Groo states that King Kohon (a former employer of Groo occasionally referenced) used to expel anyone who moved his hips like that from his military.
Hidden Depths: Groo CAN in fact make some pretty decent non-violent plans when properly motivated, or confronted with obstacles even he cant take down by brute force, its just that these plans tend to backfire or bite him in the ass later, so he prefers relying entirerly on his sword skill.
I Can't Believe I'm Saying This: In one mini-series, Groo became hyper-intelligent, and everyone who knew him was shocked by this. When the witches Arba and Dakarba saw him reason out a solution to a problem, Arba exclaimed, "Groo, you are brilliant!" and then thought, "There is a sentence I never thought I would say."
Idiot Hero: Really, Groo's picture should be on the page.
I Resemble That Remark: "What do you mean slow of mind?" said several pages after someone calls says slow of mind (once even to a flashback).
The dragons in Groo have a Theropod body shape with a frill around the neck.
They have plates and spikes down the back similar to a Stegosaurus.
They also have droopy parts of flesh often around the head.
Dragons in Groo can often breathe fire
In contrast to the depiction of most western dragons they do not have wings and can't fly even if they do.
They are mostly green but other colors have been depicted (there doesn't seem to be any difference between them).
Origin Episode: One story shows Groo early in his life as a warrior, as well as where he got his iconic swords, beginning as a soldier for the warlord Fuchikaka, and, after blowing a major battle singlehandedly in an Establishing Character Moment, is captured by the forces of the cowardly Emperor Sakisama, whom he is a dead ringer for. He is trained to replace Sakisama on the battlefield to make it appear as if the emperor has become a skilled warrior, and is given his swords as part of the deal. By the time the story is over, Groo has not only managed to screw up the assignment, but also caused his entire village to be massacred, and escapes the carnage to begin Walking the Earth.
Overt Operative: Proof of the "Greater Fool" theory: Groo was once employed as a spy.
Groo(to the people he's spying on): No one must know that I am a spy! Make sure everybody knows that!
Psychic Block Defense : Done for laughs in one story, where an evil wizard is attempting to read Groo's mind... and fails spectacularly, because there's nothing to read.
Rhymes on a Dime: The Minstrel. Sergio apparently dislikes writing dialogue for the character since English is his second language.
Truthfully, Evanier write the Minstrel's rhymes, but he does hate it, because its time consuming to think them all up.
The comic even has a running gag that there is only one joke, yes a running gag about a running gag. It's even supposedly caused people not to read the comic because they heard it has only one joke.
Schmuck Bait: Groo himself is seemingly irresistible Schmuck Bait for anyone who needs a dupe for their cunning plan: it almost always ends up back-firing. Except when the manipulating character counted on it backfiring - for instance, taking out a loan to buy a massive insurance policy on a ship and then inviting Groo aboard will result in the vessel not sinking - with catastrophic results for the would-be insurance fraud.
Another example: Drumm cannot resist calling Groo a mendicant despite being beaten up for it every time.
Shrouded in Myth: In one story, the tyrant Pipil Khan keeps hearing stories about all of the battles Groo has won and the carnage he has caused, and imagines that Groo must be a huge, fierce warrior with demonic powers. Then the real Groo finally shows up — a rather short, scruffy, plump guy with a broken nose and stick legs — and Pipil Khan dies from shock.
Suspect Is Hatless: In one issue, Groo asks a passerby whether he has seen the man who was standing next to where Groo was standing a while back.
The Uriah Gambit: Those who encounter Groo keep sending the titular character against impossible odds with little support both to get rid of Groo and sometimes serve as a distraction (This includes his family and "friends"). But since he's a One-Man Army and has the element of surprise (since no one would be stupid enough to attack, except Groo) he succeeds with the unintended consequences on those who sent him.
Walking the Earth: Because Groo causes trouble everywhere he goes, he has to keep wandering.
What, Exactly, Is His Job?: A running gag is what, exactly, does Mark Evanier do (besides answer the letters page). Even his job description on the masthead changes every issue to something silly or bizarre. In reality, he is essentially the comic's co-plotter and script writer/editor.
The World Mocks Your Loss: When Groo thought his dog Rufferto was dead and that Groo had eaten him he kept seeing objects that reminded him of Rufferto's coloring.
Groo's faithful dog Rufferto is based on... Sergio Aragonès' faithful dog Rufferto. The "real" Rufferto occasionally appears in Sergio's autobiographical cartoons, and is drawn exactly like Groo's dog.
In these autobiographical cartoons, Sergio's wife Charlene is drawn exactly like Chakaal.
The characters of Weaver and Scribe are based on Mark Evanier and letterer Stan Sakai, respectively.