how to work with brick?

I always have a slug problem in my gardens, so I want to encourage frogs and toads to live here.  They eat slugs.  I know I also have toads, because I accidentally picked one up yesterday, thinking it was just a clod of dirt to push back into a hole I dug.  I made an audible yelp when the clod of dirt moved in my hand. 

I want to make a toad house (or 2 or 3) to encourage toads to stay around plants that I frequently lose to the voracious slugs.  Porcelain ones look nice, but porcelain outdoors will not survive a harsh winter in Minnesota.  I need concrete to endure the weather.

Thin bricks look like the material I need, but how do I connect them into a whole structure?  I think mortar would work only for stationary objects.  These "houses", though, would likely be picked up and relocated occasionally.  I need something substantial to hold the bricks together.

Any ideas?  This kind of work is not my strong suit.