Personally, I've always been kinda "on the fence" about the Mummy creature, in general. Of all the old monsters you can think of, he's probably the least intriguing to me. It's really just personal taste, but I feel like the others have more to offer in some way. I also find that the metaphorical scare of this monster comes from something I've never really had to think about, for myself.
Taking place in 1921, Egypt, a field expedition led by Sir Joseph Whemple (Arthur Byron) uncovers the mummy of prince Im-Ho-Tep (Boris Carloff), along with the Scroll of Thoth, which holds the power to bring the dead back to life. Upon inspecting the mummy, Dr. Muller (Edward Van Sloan) discovers that the prince must have been buried alive. One night, Whemples assistant, Ralph Norton (Bramwell Fletcher) reads the scroll out loud, and prince Im-Ho-Tep's mummy springs to life, driving Norton insane.
Ten years pass, and disguised as a modern Egyptian named Ardath Bey, Im-Ho-Tep finds Helen Grosvenor (Zita Johann). She is seen by him as a reincarnation of his former lover, Princess Ankh-es-en-amon. We discover here that he was condemned and buried alive for sacrilege, upon trying to resurrect the princess in his previous life. This leads to him wanting to kill, mummify and resurrect Helen so they can be together forever. So really, Brenden Fraser's 'Mummy' movie wasn't quite as far off as I may have originally thought.
As for the whole execution, as mentioned before, the Mummy was kinda always on the bottom of the list for me as far as these old school monsters go. It's not really for me, but it's also not without its moments. There are some good close ups to the Mummy's face, and Karloff does a pretty good job at seeming like a man out of time (at least for 1932). For some, the underlying concepts of this movie are pretty scary, but again, I can't relate to it as much as something like Franenstein being misunderstood, or the Wolf Man dealing with the beast within.
I suppose this is largely about desire, which is definitely relatable, but not to such an insane degree. Again, the horror here comes from being in Helen's shoes, and this is a bit closer to the... romantic?... concepts behind 'Dracula'. The difference being that Dracula's a bad ass, sexy dude, and Im-Ho-Tep has next to no personality, other than wanting to be with his one-and-only for eternity.
So, this is a classic in its own right, and the Mummy is still classified as one of the several classic Universal monsters, so I'd recommend checking it out due to that. But it's also my opinion that the '99 'Mummy' is just a lot more fun (dated CG effects aside). This one's kinda dry and humourless, and though it's only about an hour and a half, I felt it dragging after a while. At least with '99 you get the likes of O'Connell, who's basically a mish-mash of Indiana Jones and Star Lord. It's also just more exciting, overall, and the Mummy feels like much more of a threat. That's just my humble opinion though.