Toilet frequently/randomly clogs

[lordofthethighs]

This is a perplexing problem which we've been living with for a few years now. We have 3 bathrooms in our house - 2 upstairs, 1 downstairs.
One of the upstairs toilets (it's always the same toilet) will clog without warning. And sometimes it's a real ***** to plunge whatever it is loose. It occurs so frequent that I have to flush it first as a test before I use it, just to be on the safe side. The other toilets are not a problem.

We have 2 middle school children, and I doubt they're throwing their toys into into it.

I'm really baffled. I call this toilet the UFO - 'Unidentified Flushed Object' because my theory is maybe there's a toy/pencil/crayon/whatever from the kids a long time ago and it's wrenched in the porcelain winding ways causing the random bottleneck?

 

[Caduceus]

You could be right. How would you like to proceed? Drain and pull the toilet and inspect it as well as the drain or try a closet auger to see if anything can be pushed out or pulled out of the toilet?

 

[lordofthethighs]

I'll be truly amazed if my hunch was correct. Any other possibilities if nothing is found after I check it.
If I use an auger I might not know if it pushed something through will I? I mean it's possible I won't feel it through the tool.