You can have a scare. And you can have a fear.

But you can have a fear of something, like bats, maybe, whereas you can't have a scare of something. (Although "a scare of" would probably be a good name for a collection of certain animals, like bats, maybe.)

And you can be scared. And you can feared.

But you can be scared of something, like bats, whereas you can't be feared of something, like bats.

And you can scare. And you can fear.

And you can scare something, like bats, and fear something, like bats, but you're not doing the same thing when you do.