An anarchist that terrorizes other human beings. I've seen em. Their bigger assholes then the rest of the terrorists groupings.
Terrorism is an ideal extremists use to further exert their beliefs through the expression of terror or violence. So yes, its real. Anarchy and terrorism are practically the same thing if a government is already in power. Anarchism is basically in it's truest form 'No Government' so really, in order to achieve Anarchy one would have to do 1 of 2, relieve the current power through violence (terrorism) or persuade the proletariat to riot and or protest. (Take the government over from the inside) - ( Eat the Apple, at it's core - Jon Michael Turner )
All anarchists are terrorists. All muslims are terrorists, too. And communists, jews, capitalists, christians, and many more! It just depends who you ask.