His tail is up and he is snorting like a steam engine.
When he rushes toward you in this attitude it looks very much as though he were charging you with the purpose of trampling you to flinders.

As a matter of fact, or, rather, opinion, he is merely trying to locate where you are in order that he may run the other way.

He looks terrifying, but in reality is probably badly terrified himself.

He would give a good deal to know which way to run, and finally becomes so excited and nervous that he starts frantically in some direction, hoping for the best.

If this rush happens to be in your direction you call it a charge from an infuriated rhino; if not, you say that he looked nasty and was about to charge, but finally ran away in another direction.