You Spineless Pansy

Recently, in the course of writing a poem, I used a fairly peculiar phrase.
"- It's like lacking in a spine -"
What does that even mean? What was I talking about?
It was weird alright. Who says that? Other than me, at least? And more importantly, I must ask yet again, what does that mean? 
But I got to thinking about it, because my thoughts are generally worthless like that, and the question became more baffling yet!
What would a person look like without a spine?
Honestly, I'm dead serious here. What would someone look like if they didn't have a spine? There's lots of possibilities. Indeed, their whole body would be all types of screwed up. For instance, how would their legs support them? Would they even be capable of brain function without a spinal cord? Is it possible that without a backbone, you couldn't have a head, either?
I remember in elementary school, they used to say that without your bones, your body would be like a sack or bag full of jelly. So would your upper half be like that, if you didn't have a spine? Hmmm...

Lady: Oh, officer! I just walked into the kitchen to find him like this! Do you know what's wrong?
Police Officer: Ma'am, I'm sorry to inform you of this...I'm not even sure quite how to put this... Your husband doesn't have a spine.
Lady: What?! How dare you say that!
Police officer: No, really, he literally DOES NOT HAVE A SPINE.
Lady: Out! Out now! Get out of my house! *hits over the head with a broom*

Then again, that's probably a lie, like the rest of elementary school.
So. Naturally, there are real animals without spines. Invertebrates. What's to say that the entire human physiology wouldn't be altered for a spineless person? What's to say that they would look anything like us?What's to say that people wouldn't look like... jellyfishes? A spineless person could look like a jellyfish, I guess.

Umm... No.
Okay, what else doesn't have a spine? Oh, I know! Insects. They've got exoskeletons, right? I suppose it's a technicality, but they don't have spines. A human-ant, maybe?

Oh god. Please, please, no. No. Not cool.
Okay, so what else doesn't have a spine?
You know what - never mind. I think I've discovered why human anatomy is the way it is. And why we are bipeds. And a number of other things, including why we aren't actually spineless. Maybe I should stop thinking about this.
Hey guys guess what!
Today I learned why people have backbones.