Many artists living/dead have been influential, and some that came after had/have no problem admitting they were heavily influenced by singing and/or lyrical style, dance moves, etc… But I’m sure there are some artists no one would dare to emulate, because it would come off silly. I’m guessing most candidates will be lead singers. I think most would laugh at someone trying to pretend to be Jim Morrison, for example.
If we include “extreme” artists, there are going to be a lot. Tiny Tim, for example.
Tom Waits might be a good example.
As an artist, yes - people would definitely know who’s style you were ripping off. On the other hand, didn’t Waits successfully sue some company who used a Tom Waits sound-alike in an ad campaign? So, someone tried to emulate him, unsuccessfully.
My first thought was Robin Williams. Any comic now who tried to act like that would probably get booed off the stage.
Surely the greatest artist ever in his chosen field, I don’t know of any effort to emulate Le Petomane, the world’s greatest fartist.
Captain Beefheart is the obvious musical choice.
Frank Zappa
You haven’t heard of Mr. Methane?
My thinking is that I can’t think of anyone who’s tried to emulate Willie Nelson, at least not well enough for me to think “This guy’s trying to sound like Willie”.
OP includes the word “great” so the best answers are probably not going to be well-known artists (greats within their genre). It’s an interesting question.
On the guitar, maybe Albert Collins, Stanley Jordan and Jeff Healey. Unusual for different reasons, not sure if others have copied those unusal qualities.
Nobody sounds like Mark Knopfler either.
Andy Kaufman?
I’d almost vote for David Gilmour. I only remember three times I’ve heard something even close to his guitar: Silent Lucidity, which they claim is not Floyd-influenced and is the weakest case of the three anyway; the guitar soloes on So Red the Rose by Arcadia, which I thought sounded like Gilmour and turns out to actually be Gilmour, and the lead guitar on The Final Cut by Coheed and Cambria, which technically invalidates Gilmour since the title of the song makes it obvious they’re trying to emulate him, but I don’t think Coheed would say they’re particularly influenced by Gilmour.
I think that both Ian Astbury from the Cult and Glenn Danzig sound a lot like Jim Morrison.
ETA: heck, I forgot, Astbury even once sang with the Doors as an ersatz Jim Morrison. It was an obvious choice.
Knopfler, like Zappa and Gilmour, has such a unique guitar tone that he’s hard to emulate. Same with Carlos Santana.
ETA: and was there ever a drummer who sounded even approximately like Keith Moon?
I saw the “20th Century Doors” thing about 2002ish… I didn’t like his voice, but I didn’t think he was copying, but then again, I’ve never listened to the Cult much.
I don’t know if you ever heard The Butts band, but Densmore and Krieger formed it after those two post-Morrison albums. They did one album with one singer, and then got another singer. Two different voices, but kinda soul-inspired.
Bobby McFerrin?
In a similar vein, Al Jarreau.
All three instrumentalists in The Who probably qualify, though, for completely legit reasons (he plays with The Who now), Zack Starkey (Ringo Jr.) comes real close to emulating Moony’s style.
Sam Kinison (oh-oh-ohhhhh!).
I suspect some of the other shock comics, like Andrew Dice Clay, may also qualify - they developed quite a niche that is too recognizable for someone to mimic.
I’ll have to respectfully totally disagree about him even being in the ballpark of Keith’s drumming.
http://www.ljhelms.com/pet/_pujol/thestory/retro.htm
*His former boss at the Moulin Rouge, hardly content with the size of his settlement versus the loss of his greatest moneymaker, immediately debuted a new star: La Femme-Pétomane! Her act, of course, was a blatant rip-off of the pioneering Pujol. Adding insult to injury, it quickly became apparent that (on top of everything else), this woman had no natural talent. It was revealed to a furious Le Pétomane (who could hardly contain himself) that his female rival kept a bellows hidden beneath her petticoats! Sacre bleu! *