Classic interstellar joke

The commander of the base keeps a cow, which is very powerful. No one can compete with it. So the commander issued a notice: if someone can beat my cow, I will marry my daughter and nurse MM to him. The condition of victory is to make my cow shake its head, then nod and jump into the moat.

A fire fighter came to the commander and said yes. The commander is a little incredulous.

So the flamethrower came to the cow and said, Do you know me? The cow shook her head. I heard that you are awesome? The cow nodded. The flamethrower took the gun and set the cow's tail on fire. The cow jumped into the moat in pain. The commander looked at it: Holy shit |! It's that simple. It is disgraceful to marry my daughter to a fire-breathing soldier, so I said to the fire-breathing soldier, what skill are you? If you can make my cow nod first, then shake its head, and then jump into the moat, I will really marry my daughter to you. The flamethrower came again and said to the cow, do you know me? The cow nodded. Are you still awesome? The cow shook her head. The flamethrower picked up his gun and said, you know what to do, right? Looking at the burnt tail, the cow jumped into the moat.