Summer and Scooby Doo are a great mix, and beach settings suit the franchise well too. Have always loved it when creepy and suitably bizarre mysteries are investigated and solved in exotic locations, and "Reef Grief" definitely has that. "Reef Grief" was one of those episodes that left me mixed on first watch and where memories before rewatching were quite vague. But it is because so many other episodes of the show have villains so memorable and have things that set them apart.
There are episodes that didn't do much for me on first watch and where memories weren't vivid and weren't much better on rewatch, "Wrestle Maniacs" and "Diamonds are a Ghoul's Best Friend" being the prime examples. Then there are others that are much better by today's standards, have a much higher appreciation for "A Scooby Doo Valentine" and "Camp Comeoniwannascareya". "Reef Grief" is in the latter category and also has an interest point not picked up upon on first viewing.
The Scooby Doo franchise always delivered when it came to effective settings, that are a mix of exotic, haunting or a bit of both. When the setting is used well too, it makes things even better. The beach setting is immesely vibrant in the animation and made me want to be there monster or not. Could also feel its warmth. Even better is the character design and animation of the Reef monster, very creepy and not goofy. It does stand out from the rest too.
Musically, "Reef Grief" is great. Very catchy and not discordant with the action, the chase song is one of the instances where the energy that is already present in the story is enhanced. The theme song is one of the franchise's catchiest. Most of the humour is funny and easy to endear to, can never get enough of Shaggy and Scooby. The voice acting is on point.
Did like the mystery on the whole. It is at times on the familiar side, but it does stand out for the cool looking and creepy Reef Monster and also the knockout ending that is even more unpredictable than those for "Toy Scary Boo", "Mummy Scares Best", "Simple Plan and the Invisible Madman" and "Go West Young Scoob". Up to this point, it was pretty unique for the franchise too.
By all means, "Reef Grief" isn't perfect, with occasions where it looks rushed and when the material is a little forced. Do wish too that more explanation was given for how Shaggy and Scooby nearly got dragged into the sea.
In short, very good and another better than remembered episode. 8/10.