My funny third formal supervisor poking a banana

Why there's a "formal"?Because he is my appointed third supervisor, in fact, I have FIVE supervisors for my master project!! where the informal third one is from other school and the informal fifth one is the informal fourth one's wife, where, formal third supervisor=informal fourth supervisor!!sounds complicated huh!!
Hahahaha~~mayb there's some problem with my categorization!
That day, one funny incident happened.
In the morning, I went to look for my third supervisor. He guided me some lab work and then he went back to his office to get busy with his own stuffs, saying that if I have finished my labwork I can go n give him a shout. In that morning, there's no banana on his desk.
After I finished my labwork, I went to knock on his door. "Yes~~!" he answered to my knock and once i opened his door I saw him working on his desk--next to a banana. Why I noticed that banana? Coz that's the only thing that is not supposed to be in an office!! (although this is just my opinion) (I noticed that people here like bananas, they eat them during study leave until finish exam! Brain food perhaps?)
Okay, it doesn't matter. Afterall that is NOT mine. I started to report my lab results and asked him some of my doubts regarding my project. He was explaining to me, while moving his hands around just like a normal gesture...until he poked the banana on his desk. (Actually his index finger was pointing downwards like pointing something that is not there while explaining)
Initially I was trying hard to understand what he was trying to tell me, until I saw a sudden change in his facial expression--it was like a face full of surprise from a "big new discovery".
IT'S BECAUSE OF THE BANANA!
He asked me:"How did this banana get here?"
I said:"It is already here when I came in."
He:"This morning?"
I:"Nope, just now."
And we both bursted into laughters!! How can he not noticing something that has been jus beside his right hand for one or two inches away? Did the banana look transparent to him? He thought it was a cell phone or pen? Or he is used to work with a banana by his side? I guess he was just too busy that he was too concentrated to his work until not knowing something appeared (or lost too?) around him.
..........It's my informal fifth supervisor, she put it onto her husband's desk........