It’s a prank with a soft-serve 
ice cream cone.

First, watch this typical "coning" prank. (That’s "cone-ing", not "conning".)

Epic Coning Reaction

As you can see, the coning prank occurs when a prankster orders a soft-serve ice cream cone from a drive-through restaurant window and then grabs it by the ice cream instead of by the cone.

Of course the prank is filmed in hopes of getting a great reaction from the befuddled employee.

The Museum of Hoaxes analyzed this prank and identified this behavior as a form of breaching experiment, where the jokesters violate an unwritten social rule and then see how others will react.

However, the employee in the next video has had enough. Watch as he reverses the experiment and succeeds in breaching the prankster.

McDonalds Worker Rejects Prank

Coning: A Strange New Prank, The Museum of Hoaxes>>