Combee has a 1/8 of being Female. Assuming that this isn't Masuda Method, there is a 1/4096 chance of being shiny and a 1/16 chance of that shiny is a Square Shiny. Now, you have a 3/5 chance to pass down that HA to tha offspring. Calculate those lovely odds and you get 0.0000011444 or **0.00011444% chance. ** However, if you do Masuda Method, your Shiny chances increase to 1/683, which brings your odds to **0.00068631%**. Now, let's say you really wanted this Shiny Combee and got the Shiny Charm, bringing those odds to 1/512. Your new odds would be a nice **0.000915527%**

Source: Combee pages, pages on breeding, square shiny pages, shiny odds, etc.

If my math happens to be wrong in some fashion, please comment.

Thank you TY!