Seriously Scary

What scares me most?
It's not a ghost, no nothing of the kind.
Not old black cats,
nor flying bats, I think that they're just fine.
Not fond of snakes,
but I don't get the shakes, unless they're in a pit.
What? Space aliens?
No, not scared of them. Guess I'll just get down to it.
They're not large in size,
but they've got weird eyes; antennae on their head.
They're mostly brown,
when they come 'round I'd just as soon be dead.
They creep and crawl,
up the wall, across the ceiling. too.
I know they're always there,
but I don't care if they just stay out of view.
They've got many names,
though they're all the same, some of them can fly.
They're not very clean,
and they make me scream, every time one goes by.
Survived the ice age,
and some even say they'd survive nuclear attack.
You may think they are gone,
but before long, they come marching back.
You probably already,
know where I'm headed, the thing that scares me most,
is the water bug,
the Palmetto bug, the damned, ugly, nasty cockroach.