If I were taking a very quick look at him, I'd see beagle or beagle mix there. But anything longer than that I'd start to think cattle dog, or that ilk.
Ruth & Gibbs
In all honesty, he just confuses a lot of people. Half of the world seems to think he's about 10-12 weeks old and ergo huge, the other half thinks he's an adult small dog. BC people in general see BC (when actually watching him do stuff as opposed to stand around), ACD people see ACD, largely in his face, and yeah, the fading coloration/saddle make people see beagle/hound. The odd person for reasons that confound me REALLY think he's a GSD X.
Honestly, I just laugh - not mocking, but amused. I am going to quickly reach the point of responding to 'what is he?' with 'a dog' though, just because exhaustion. I'll make a point to do it kindly though
Mostly, he's just a great puppy. A slightly strange puppy sometimes but a great puppy.