(Noun)- the act of leaving mildly inappropriate and wildly unrelated pictures, gifs or anything interesting/funny from the internet in obscure facebook locations. Pictures and gifs do not necessarily have to come from Tumblr, but the plethora of useless and fascinating images from Tumblr make it the perfect source of arsenal for a Tumblr war. These wars can involve two or more face-book friends, and they begin when one posts an unrelated image. All subsequent postings must be more ridiculous and unrelated the previous ones and the war ends when the players are satisfied with the amount of random crap smeared on someone's page.
Example 1: The TUMBLR WARS started when I left a gif of charlie sheen dancing to dub-step under my best friend's profile picture. So my friend posted a picture of a pink poodle dressed as a clown and other friend posted a picture of a half naked hairy drunk man.
Example 2: I posted a status about my dead grandmother so of course my best friend started a TUMBLR WARS- posting ten pictures of sponge-bob under the status.