I rolled randomly, got CR 7, rolled again, and ended up with a gargantuan animated object.
Well crap.... maybe repeated castings of Create Water to create mud against the wheeled variety? Too much would depend on the type of object. Let's try again.
This time I got a 12, which gives me..... Roper. I must say, I'm at a loss as to how I'm going to handle a roper with cantrips. It's vulnerable to fire. How about Dancing Lights, Ghost Sound, and judicious use of the bluff skill to convince it that a torch-bearing mob is on its way?