Am a big fan of anything Sherlock Holmes, as well as anything Scooby Doo. Both have proven in previous incarnations in the Scooby Doo franchise to gel extremely well together more than once. And very memorably in 'Scooby Doo and Scrappy Doo's' "The Night Ghoul of Wonderworld" and 'The New Scooby Doo Mysteries' "Sherlock Doo", both among the best episodes of their respective shows. My first watch of "Elmentary My Dear Shaggy" was very positive.
Same goes for my rewatch when rewatching 'Scooby Doo and Guess Who', an uneven show with some guest stars not working and some mysteries being stronger than others but on the whole surprisingly good. For me, "Elmentary My Dear Shaggy" is by far the best of the four episodes up to this point, being the only one to be above good. Also consider it one of the show's better episodes, with one of its best guest stars.
"Elementary My Dear Shaggy" has so many good things. The animation has a lot of atmosphere, rich colour and even richer attention to detail. The music is dynamic and groovy, also loved the modern spin on the iconic classic theme tune for 'Scooby Doo Where are You', although it is too short. The voice acting is very good, with Matthew Lillard nailing it as Shaggy.
One of the biggest strengths is Sherlock Holmes himself, easily the best guest star up to this point and a match made in heaven for the gang. He's funny, clever and full of authority as well as very true to character, his madder moments shine especially. Love the chemistry between him and the gang. Also love the setting, very authentic and imaginatively used. While Shaggy and Scooby are funny and lovable, the treat was Velma in the Dr Watson role, very similar to the Dr Watson-like role she had in "The Night Ghoul of Wonderworld".
Writing is especially good in the humour, which is classic Scooby Doo. Endearingly goofy but also quite smart, not just with Shaggy and Scooby but also Holmes' madder moments. The mystery is full of energy and atmosphere and is eventful and lots of fun, nothing thin and very little draggy here. The screaming skulls are genuinely eerie, with their Spooky Space Kook-like designs being particularly memorable. The individual personalities of the gang shine, Daphne's quirkiness is fun and Fred isn't dumbed down. The funny Scooby and Shaggy and Velma shine more.
However, the reveal is slightly too obvious and rushed.
Did feel too that while visually creative and fun, the chase scene is a little too dragged out.
In summary, very good. 8/10.