a horrible virus that attacks any new tumblr users. there is no way to avoid it once you've made an account. it WILL find you and eat away at your computer. the only way to not get it is to just stay away from tumblr.com.
friend 1: hey i just made a tumblr! follow me?
friend 2: oh god! quick delete it, or else you'll get 5T4S!
friend 1: but you have a tumblr...
friend 2: yeah but it only attacks new users starting after 2011, seriously you have to delete it ASAP. it's the worst virus you can possibly get!
friend 1: oh lord okay! -deletes-