When you look at a barnyard scene in a children’s book, you see animals of well-known kinds: the horse, the cow, the pig, the chicken. When you listen to a recording of a rock band you similarly recognize guitar, keyboard, bass, and drums. Homey.
Sometimes a lion or an octopus shows up in a funny barnyard, and sometimes you hear a sitar or an ocarina in a rock song. A theremin might fly through like an unexpected condor. The Exotic Instrument Hook works well partly because we do identify the instrument and welcome it on this special occasion.
But what if you hear something you can’t type at all? What if—what is that, adding those rhythm fills in “Hurry Up”?
Bear in mind, this is on a 1970 album by Poco, so we can’t give the catch-all answer “synthesizer.” It’s a veritable mystery instrument. Now that I’ve read up on Rusty Young, I know he’d been experimenting for years with various ways of producing rock noise with a pedal steel guitar. For one thing, he knew how to make the pedal steel sound like an organ by playing it through Leslie speakers, which is apparently what’s happening on “Hurry Up” and three other tracks on Poco. But while his playing is totally convincing and doubtless takes advantage of both organ and guitar qualities, it can’t be resolved into either a kind of organ or a kind of guitar. It’s an ambiguous mixed beast, a hippogriff.
This rivets my attention on his sound. I hadn’t realized before how much my engagement with the instruments in music depends on a sense of each one’s attack: picking on strings, pressing on keys, beating on skins. My sense or at least my assumption about the musician’s physical initiative is a ground-level hook that plays a considerable role in driving the action forward. But the hippogriff has no mane like a horse, no tail like a bird. We have to give it more of our attention just to figure out what the hell it is.
Here is what Young can do soloing in this voice:
And then in the instrumental workout on side 2 of the album:
Near the end of “El Tonto De Nadie, Regresa” he switches over to a drastically different, more guitarish sound. The hippogriff might do anything!
The hippogriff’s appearance really is rare. I don’t know where else to hear it than on Poco. That LP sleeve has some odd feathers sticking out.
 Listening further back, I hear it on “Nobody’s Fool” on the first Poco album (1969).