From CBS News: What is Antifa? ‘In the USA, the right-wing media blames antifa members for rioting and looting. Democrats have also condemned such violence, but many on the left say the rhetoric about antifa (i.e., anti-fascist) is greatly exaggerated, and that it's less of an organized movement than just something of "an idea."
Swiss Info says: ‘Antifa, designated by US President Donald Trump as a "domestic terrorist organization," is a diffuse "anti-fascist" movement of left-wing activists that experts say is more of a political ideology than an organized group…’ We read: ‘Antifa, from the word anti-fascism, was already in use in Germany in the early 1930s, where "anti-fa" socialist groups tried to oppose the rise of Adolf Hitler's Nazis…’ 
For some reason, perhaps to escape the obvious point that our fathers and grandfathers fought, precisely, against fascism in the 1940s, the American right pronounces it ‘antee-fuh’ rather than ‘anti-fah’!
But much of what politicians say about antifa isn't quite true. Here's what antifa is and what it isn't.
Antifa is not a highly organized movement, nor is it merely an idea. Antifa is a loose affiliation of local activists scattered across the United States and a few other countries.
‘In general, people who identify as antifa are known not for what they support, but what they oppose: Fascism, nationalism, far-right ideologies, white supremacy, authoritarianism, racism, homophobia and xenophobia…’
Flag shaggers, antifeminists and fake-news merchants.
Some of us don’t like cockroaches either.
Here in Spain (where no one had ever heard of it until now) La Razón recently ran a piece titled ‘Antifa: the masked figures who want to stifle public debate. The United States is pushing to outlaw them, Spain to welcome them’.
Apparently, if you believe La Razón, which you most certainly shouldn’t, the country is swarming with them. The Spanish ABC posted in October: ‘Trump orders foreign anti-fascists to be designated as terrorist groups. A Trump advisor tells him to look at who belongs to these groups in Spain’.
No one - is the short answer to that, because it’s an opinion rather than an entity. 
Nevertheless, because it’s worth a shot, the Trump-admirer Santiago Abascal, the leader of Vox, has recently called for antifa to be declared as a terrorist organisation in Spain: the proposal to be debated in the National Parliament in February.
Perhaps, on sober reflection, what we really need to do is to ban the anti-antifa program.
I suppose my main worry is this:
Is Ol’ Santi planning a Spanish version of ICE (the United States Immigration and Customs Enforcement) where lump-heads get to wear combat gear and a mask as they round up anyone who looks like he didn’t come over in the Mayflower; maybe make it a more Spanish version, something like Franco himself would have approved of?
He'd need the approval of whoever will be running the PP when Spain next goes to the polls.