Because they contain a lot of sugar.

When you handle an ice cube, the surface of the ice melts with the contact of your skin, so there is a layer of liquid water against your finger. That water can’t be colder than 32F so the ice cube will always feel 32F.

Sugar, like salt, lowers the freezing point of water (this is why salt gets mixed with the ice in old-fashioned ice-cream freezers). So when the liquid (syrup, really) of the banana melts against your skin, it can be considerably colder than 32F. That super-cold liquid pulls heat from your skin much faster than ice-melt does.

@thorninmud Gave you the technical answer. I’ll just add that we’ve found that peeling and cooking them before freezing makes using them in recipes later a piece of cake—banana cake.

My wife got an incredible deal on a 24 ct. box of Del Monte bananas at the Haymarket open-air market. Interestingly, it says on the box, store at 57 °F. So if you want to keep them available for use fresh, a wine cellar would be perfect.

I could ask a grad student to make this their dissertation.

My guess is cold banana mush sticks to your fingers…