In order to get the special cream banana you need to get 7,000 bananas. Once you've achieved this you need to click each individual banana once with your mouse. After each banana out of the 7,000 has each been clicked you'll get the special cream banana that serves no purpose other than to flex. A tip is to click each banana as you spawn it in as it's nearly impossible to click all 7,000 bananas after you've spawned them in.