Death Rowl is the Metalhead version of a "Freestyle Rap Battle" where 2 or more people gather in circle. Making up lyrics and literally screaming them at another. Often lyrics mock the person they are battleing. The audience judges which is more "hardcore" based on 'grittyness' of the voice, how long they last, speed, and lyrics (if they can understand them)
It is quite uncommon to see a death rowl. Growling is mostly used but Whispering,Specking and Raping can also be applied to one's technique (depending on what style of Metal they perfer)
kid: Death Rowl!
Metalhead: yeah, *screams words*
Metalhead 2: *screams words*