Sound distortion software?

Ok so I have no clue what Im doing and Im really tired but here goes. I'll just be direct, I want to create cool and unique monster roars using super distorted sounds for a personal project I'm fooling around with. I want to be able to plug in a sound I have recorded irl with a mic already and be able to distort it in multiple ways and add effects etc.

So any information really helps. Do I have to get some sort of music editing software or are there programs specifically for distorting/editing/affecting sounds? Latter being preferable, of course, if there are such programs. Open to any suggestions. I'd prefer free programs but price wont stop me from taking a look at stuff. I want everything to turn out awesome so I might just go with it. I have no knowledge of what is out there so actually anything I can use is appreciated. Thanks in advance, and hopefully you guys will be able to see some art and other sneak peaks at stuff later this year.

propellerhead reason is the closest I think you will get if you are looking for those dub-step style roars