I have one magic bomb in my inventory. the description is:

A round glass jar with sleeping gas produced by those mad alchemists from the State Lab. Allows you to catch a Wild Pet of any class with normal chance. Single-use item.

It doesn't have a "use" button, so I assume it will be used up when you place a magic catcher?  My main question is: When you place a magic catcher in the field, does it only catch a creature if it encounters one? Or does it always end up in a creature capture?

I was just confused because I read somewhere that you don't have to worry about calculating the movements of the animals when you use one..

Thanks!

Only if it encounters one. I used one once and ii came back empty handed, but then the next turn it caught one.  The only thing about a magic cather is that it can catch a species of any type, mammal, reptile, whatever. 

Thanks! But it can only be used once? Just doesn't sound like much of an advantage seeing as I rarely encounter any creatures with any catcher.

Swiftla, like Cheese already said, Magic Catcher will stay with you until he catches a pet. It's a single-use item and you can catch only one pet with one Magic Bomb.

Okay, thank you so much. I don't know why I was so sonfused! :)