Lickspittle

"Find a lackey. I cannot stress the importance of this enough. It's a crucial step on the ladder to becoming popular. How are people going to know you're awesome if there's not some other party reminding them of it on a regular basis? ... Don't pick someone prettier than yourself or with high self-esteem. The thrill of living vicariously through you, the superior person, should be their greatest joy in life."

- Memoirs of an Internet Legend

Pretty much the lowest of the low, the Lickspittle is someone who willingly makes themselves the whipping boy of someone with power and/or fame. More than a Yes-Man, more even than a Professional Butt-Kisser, the Lickspittle sets no limits to the depths to which he will abase himself in order to curry favor with the object of his adoration. If they have an opinion, he'll copy it. If they're in an argument, he'll take their side. If they ever suffer a moment of self-doubt, he'll be there to cheer them up with some assurances of how great they are. He'll eagerly sacrifice friends, family and dignity to prove his complete and utter worship. Further, he'll eagerly act as their attack dog -- lashing out, insulting and dragging down anyone who dares express anything but utter worship for them.

Picture the small kangaroo from Horton Hears a Who!.

Compare Professional Butt-Kisser and Yes-Man. Where the Yes-Man agrees with the boss's opinions and decisions, the Lickspittle agrees with everything about the boss. Where the Professional Butt-Kisser is obsequious, the Lickspittle is disgustingly obvious about it, to the point of having no pride or self-respect, while at the same time unswervingly loyal to his "master". Further, this behavior is obvious in-universe, leading other characters to view the Lickspittle with no small amount of disgust and/or pity.

Interestingly, the Lickspittle doesn't necessarily have to like the target of his fawning sycophancy; it's common to find a Lickspittle who actually loathes his "master" -- but he continues his behavior because he's riding the master's coattails into a position of privilege, wealth and/or power.

"Lickspittle" isn't one of those Esoteric Trope Names we're famous for, by the way -- it's a standard English word dating back to 1825, meaning an obsequious brown-nosing toady -- in case we haven't already made that clear enough.

Literature

 * Peter "Wormtail" Pettigrew from Harry Potter appears to have been this for both the Marauders and Voldemort. The way he acts toward Harry upon being revealed in Prisoner of Azkaban is classic Lickspittle behavior.

Live-Action Film

 * The Red Queen's Court in Tim Burton's Alice in Wonderland. The Mad Hatter actually uses the word "lickspittle" when describing the court members to the Red Queen.
 * Monty Python managed to make an entire religion look like the Lord's lickspittles in The Meaning of Life's school chapel scene.
 * LeFou, from Disney's Beauty and the Beast, is Gaston's number one lickspittle, but most if not all of the townsfolk seem to agree with his opinions.
 * Hollister, the salesman during the "shopping for Vivian" sequence in Pretty Woman, who very eagerly accepted Edward's request for "major sucking up".

Western Animation

 * Mr. Burns from The Simpsons uses the term to describe Smithers.

Video Games

 * Elliot, assistant to the evil queen in Jagged Alliance 2 remains loyal despite repeatedly taking physical abuse from her up to and including being shot in the head, even offering to clean up the mess left by it.