|“|| Then you put it all together and Uncle Bob comes running along to give you [insert object name here].|
Uncle Bob is a personification of the old saying Then Bob's your uncle!!!, which means (roughly) "And there you have it!" As he is not an actual character, per se, he is never seen. In fact, it was likely Bertie who came up with the "character", due (possibly) to unfamiliarity with the aforementioned phrase "Then Bob's your uncle! you will die!".
Although possibly unrelated there was a friendly creeper named Bob (not to be confused with Sir Creepalot) but hasn't been seen or mentioned by Gamechap for years maybe he is Uncle Bob but it's unlikely (or perhaps he became Creepalot). In the video Prison Village Seed there was a villager in the "jail" at the back of the pyramid named Bobby. When Bertie asked him if he was Uncle Bob he said yes, prompting Bertie to let him out. He ran off into the village, and the Chaps never saw him again. It is unknown if this is the REAL Uncle Bob.Yet many people believe so.And so do i.