I have a new-ish WD drive that I took from a Space Monkey unit (Cloud storage device thing)

I don't know much about these things, but I am fairly computer savvy. I got a SATA(I think?)-USB 3.0 cord to plug the drive directly into the computer, however it's not showing up even in disk utility (I have a Mac)

Here is a video I made that explains more, I would appreciate any advice!
https://www.youtube.com/watch?v=KTIv_0Ol-ZE

I have no idea what Space Monkey is, nor have I ever come across it. It could encrypt your drive.
Also, I have never used the cable you're using to power on your 3.5" drive (the one that doesn't show up). However, I noticed that it just goes to a USB port and I doubt the power from a USB port is enough to spin up a 3.5" drive.
Does the drive spin up?

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I'm sure it doesn't, the USB provides only 5V

That adapter you have there looks as if it was meant to power 2.5" hard drives. No USB adapter can spin up a 3.5" drive.

What you need is something like this
http://www.newegg.com/Product/Product.a ... 6812232002

Yep, assuming it's not encrypted, and assuming the FS is Mac-compatible (f.e. HFS or NTFS).

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It seems to me that data isn't an issue and that he just wants to re-use the drive.

Most NAS devices are EXT3/4 formatted (Linux format). Your mac probably recognizes the partition table but not the file system so it doesn't know what to do with the drive. You should still be able to wipe the disk in drive manager.

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