Years ago I did some volunteer work at a local animal sanctuary, for a brief period of time. Mostly manual labor like shovelling sh!t, hanging nets, putting up fencing, distributing food/water, changing bedding/mulch, etc.
They rescued wild animals that had been injured, pets abandoned by their owners, and livestock whose owners could no longer afford to care for them. They had everything from bald eagles, hedgehogs, vultures, dogs, cats, rabbits, horses, owls, deer... if it was some sort of animal that would quickly die on its own in the wild, these people would take it in.
Most of the animals lived either in large cages or segregated in pens. The one animal that was allowed to roam the property freely was a

. It was a pretty smart creature, and knew better than to run away from its food source, or to mess with the other animals. It was very friendly, and would give you a gentle headbutt whenever it wanted attention from you. It loved getting head-scratches.
One day I was busy shovelling sh!t or whatever, and the

came up and gave me a headbutt. I turned around, pet him briefly, and went back to work. He wanted more, so he headbutted me again.
Not wanting to be distracted from all the work I had to do, I ignored him. He headbutted me again. I ignored him again. He headbutted me again, a little harder this time.
I used ignore. It was not effective.
Headbutt again, even harder this time. Annoyed, I turned around, and gently but firmly pushed him away by the horns. Bad idea. He thought I was trying to play with him. Keep in mind this

probably weighed as much as I did, if not more.
He came at me hard this time, but I was ready for it. Headbutt. Push. Headbutt. Push. The forces applied were increasing with each exchange, the

and I locked in a battle of wills.
Before long, we were both on the ground, wrestling for dominance in the mud and the sh!t.
And that was when they asked me to leave the animal sanctuary.