I like the word buffoonish.
Look at Todd, interfering in our conversations, telling us jokes about chickens crossing the road and failing to make us laugh. I cringe when he does this. He is just so [buffoonish].
A Brief History of the Buffoon
In English drama, the buffoon was analogous to one of the three stock characters in ancient Greek drama, the Bômolochus, and the other two were the Eirôn and the Alazôn.
The Bômolochus was the character who was marked by his wit, his crudity of language, and his frequent non-illusory audience address. (Interestingly, in modern Greek, the word refers to a foul-mouthed person.) The Eirôn was the ironic fellow who acted as if he knew less than he actually knew, and his counterpart, the Alazôn, acted as if he knew more than he actually knew.
Good Old Boys: "Ange" and "Barn"
A fairly modern appearance of the three stock characters is from The Andy Griffith Show, which was a popular TV show in the 1960s (and is in syndication in the US to this day). Don Knotts (now deceased) played a bumbling buffoon as Deputy Sheriff Barney Fife, and Andy Griffith (now deceased) played the people-smart sheriff without a gun, Sheriff Andy Taylor.
I say three stock characters because Barney Fife and Andy Taylor played a sort of combination of all three characters from Greek drama, and actors Don and Andy played humorously (and very successfully) off each other for a number of years.
Since Sheriff Taylor considered Barney (or "Barn," as he often called him) to be his best friend and not just his employer, he did not very often take umbrage with Barney's shenanigans. More often than not, however, the general citizenry of the town of Mayberry (the duo's bailiwick) treated Barney like a buffoon, making fun of his officious, know-it-all attitude and actions.
Andy as the Eirôn would often string Barney along, obviously for comedic effect, and at the opportune time burst Barney's bubble by exposing his braggadocio, much as Socrates would in one of his dialogs.
In concluding my expansive rambling, I think the word buffoonish is just the right word for the person you describe. Unfortunately, however, the current denotation of buffoon is simply a clown, and the person you describe is more than just a clown.