I was watching TV when the topic turned to certain celebrities' ability to beatbox. In talking about this every mention of the term beatbox was
Why is human necessary?
The use of katakana is only natural, but why take a relatively long katakana word and make it longer with a completely unnecessary word?
After going through the links in the answers and comments, I realized it was using ヒューマンビートボックス like this:
俺、ヒューマンビートボックスできるよ！ in English
I can human beatbox! that made me think it strange.