Daniel Radcliffe, forever remembered as Harry Potter, has returned once more to a fantasy setting, albeit painted in a grittier tones and inhabited by even darker mystical forces.

In Horns, director Alexandre Aja’s adaptation of the Joe Hill novel, the 25-year-old actor stars as Ig Parrish, a troubled young man suspected in the murder of his girlfriend – even he isn’t even certain of his innocence – who suddenly manifests demonic horns and the ability to compel those around him to reveal their darkest secrets.

At a press conference to promote the fantasy thriller, Radcliffe discussed how the role took him to dark places that even his stint in Hogwarts didn’t, getting through the day with two horns sticking out of his forehead, backstory behind his now-famous viral rap video, and – why not? – his review of Sharknado 2.

On the particular allure of the material:

Daniel Radcliffe: I think because Potter was such a part of my life I never think of the comparisons that other people might make, or the similarities that might be drawn – but the thing that attracted me to it was just the fact that it was so bold and so heartbreaking and beautiful, and the story of this guy’s journey was something that I really connected to. And I feel like the allegory of turning into what you are perceived as or feeling like an outsider, or being made to feel like an outsider, is very strong, and something that I – and hopefully a lot of people – will kind of connect to. And yet there was such delight in bringing from style to genre, and it was so witty at the same time as being so dark, and the love story obviously, so poignant. There was just so much going on that it was exciting.

On wearing his character’s foreboding horns:

Whenever you see a line in a script, that says, “The character has horns.” You go, “OK, well, great – in my imagination, that’s fantastic. But how will it actually look?” So the first time I saw them on, it was kind of a combination of relief, because they looked fantastic, and excitement. Because when you have something stuck to your head, that can go either way. That has the potential to look silly. And it really doesn’t. The word “organic” is one of my sort of most hated, overused words. “Just make it organic.” But they do. And they look like they’re made out of organic material, and actually coming from my head. They only took like 20 minutes to put on. They were really fast. They were very light … If this was a longer story and it went into this mundanity of life, they’d probably be used with taking dry cleaning back and coat hangers, and things like that.” They’re a very functional piece of headwear.

On his affinity for stories with “magical realism”:

Without all the other amazing, symbolic, visual elements to it, it’s a great story. And the story of this love story being the idealized, wonderful – love’s young dream that then got to grow up and still be together, and the story of that falling away – is of itself a compelling enough story. I think when you add the elements of the horns and the powers that the horns give him, that brings, obviously, an extra visual element of excitement. But also, to me, I’ve always really enjoyed magical realism, and that’s kind of how I viewed this script, originally, is just being that the whole world is very, very grounded and reality with this one, extraordinary, insane thing happening in the middle of it. Which is sort of, everything else is hurdling around.

On relating to his character’s sense of isolation:

I think everyone thinks of actors as being, like, having relentlessly glamorous social lives. And I don’t. I was never particularly – I’ve spent very little time in this city [Los Angeles]. I never want to be the actor sitting here whining about being famous. But there are elements of it that are isolating. As many opportunities and fantastic things that come into your life, there are also things that you have to struggle against. But I think the perception that actors are just at one, long party all the time is not quite the case.

On whether any of the challenges of the film left him wondering "How am I going to pull this off?"

I think actors are lucky. We have a job which becomes more fun as it becomes more challenging. We could do a day of inserts on me opening and shutting drawers, and doing close ups and stuff. That would be the easiest day of my life, but it wouldn’t be any fun. So I definitely think there were a lot of moments, particularly the breakup scene. It’s not so much that you go, “Oh, will I be able to do that?” as you go – or for me at least, I go, “We can’t not do that right. That has to be perfect.” So you approach some scenes, maybe it isn’t a good idea, but you do approach some scenes naturally with a sort of an extra element of, particularly that dinner scene, that has come back to you from several people’s perspective and is a real key moment in the film, that’s one of the great moments of why having a director like Alex or a scene partner like Juno [Temple].

On his experience working with dozens of live snakes:

Actually, I didn’t know before doing the movie if I was comfortable with snakes. Turns out I’m extremely comfortable with snakes. I may have been completely projecting human emotions onto this creature, but I became completely convinced that she was very affectionate by the end. Because they get cold. Snakes aren’t cold-blooded. This was my favorite word I leaned on the shoot: they’re poikilothermic, which means they can’t control their body temperature. So whatever temperature it is outside, they will be. So they’re freezing, and then you’re really warm so they just love you and they just hug you, but not in a constricting kind of way. So yeah, I really like them. We had one scene with a hundred live snakes, which was awesome.

On Mitchell Kummen, the young actor who plays a 13-year-old version of Radcliffe’s character:

Mitch is blond, naturally. He’s got much fairer hair than I do, and they dyed his hair on the first day. And he went back to his hotel in Vancouver, and then nobody knew what he was doing and one of the girls said, "Oh you look like Harry Potter." It made his day. He was so happy. It’s a very hard job on the casting department to cast somebody to play young me, when everybody knows exactly what I look like at that age. And they did I think a brilliant job.

On his instantly viral rap performance with Jimmy Fallon on The Tonight Show:

It was amazing because I said in an interview ages ago, it was one of those things like, “Tell us something we don’t know about you.” And I’m done so many interviews so I’m really struggling at this point to find something you don’t know about me. So I thought, “Well, I know all the words to 'Alphabet Aerobics' by Blackalicious.” And then Rob, who always produces me on Fallon, called me up when we were doing press for What If and was like, “Could you do that on the show?” And I was like “I don’t know.” I sort of freaked out. Then when we came to do it this time, he was like, “The Roots really want to do it with you.” So I was like, “OK.” But then what I didn’t realize was that I did the rehearsal, then Questlove came back into the dressing room and was like, “Yeah man, I’m going to text those guys – they’re going to be really excited. I produced their second album.” So I was like, “Oh, OK. You are friends with these guys.” So I might not have been as bold as to suggest that had I known that. But I’m amazingly glad I did it. I was shaking with adrenaline for a couple of minutes afterwards. It was awesome.

On his evolution from a child actor with a natural screen presence to an adult trying to apply craft, training and experience to his performance:

I think it was very gradual for me, in like several different stages, and still going on. So it's constant learning, isn't it? But yeah, I think 14 was probably the age where I was first like “OK, I really want to have a good at this, and I really want to do this for the rest of my life.” And I think you're old enough to know that by then. And then, really, I don't think that I got any sort of solid technical grounding until I had – was preparing for Kill Your Darlings, really and just learned how to succeed. That was when I was first taught how to like break down a script, just into very basic stuff like, what does a character want out of the scene? What are you trying to do to the other character when you say that line? It is all very basic, but I never learned it before. So I found that stuff incredibly helpful going forward over the last few years.

On whether Sharknado 2, which he was dying to see, lived up to his expectations:

It totally did, obviously! It’s fantastic. I met Tara Reid and Ian Zeiring and was able to wax lyrical about it. I have a real affection for films like that, and with the second one, they knew even more, like they were even more self aware and knew more what people liked about it and were able to make it bigger and louder and sillier and fun. So, yeah, it was great.

Horns opens Friday nationwide.