Nobody can guess what TSR was thinking when they crammed these oddities into the Monster Manual. They ran out of good ideas in the first book and then wrote several more books full of this stuff.
Zack: Be honest, Steve, how many times have you included these in a game?
Steve: I think Keith might have used them one time, but it might just be a bad dream I had.
Zack: They're manta rays as smart as people that tend to be religious vampires. That is conceptually too complicated to throw out there as a random encounter.
Steve: Yeah, I guess you have to build a whole plot around these things.
Zack: You can't just roll some random encounter dice and tell your players, "Alright dudes, you're walking along the beach and you hear some praying. You look over and you see these manta rays in a church. Some of them look really pale."
Steve: "Roll initiative."
Zack: I wonder what sort of religion they follow.
Steve: They're chaotic evil, so it's gotta be a chaotic evil church.
Zack: What was the name of Ted Haggard's church?
Steve: Was he that undead half-elf priest of Vecna from Descent into the Depths of the Earth?
Zack: Yes. That's him.
A thousand years ago, dudes were dying from splinters, but now the wizard potion that cleans our light wounds costs less than a Dr. Pepper in 1994. I love this medicinal 7up.
U2 and Apple have conspired to place a U2 album into your music in the year 2014. You own a U2 album. And you can't get rid of it.
Ron Paul spins in his chair, trying to grab his decorative antique musket but Freddy gets it first.
Zack Parsons, Steve "Malak" Sumner, and friends tackle bizarre role playing game products that make them wonder, "What the fuck!?" From the early days of Gygax to contemporary role playing games, none will be spared.