Who’s Fault Is This Joke?

A friend of mine had a strange TM symbol on his Blackberry Messenger. After talking to him about it he suddenly had the letters TM appearing after every sentance, and then eventually every Letter! I quickly went around telling some other friends and they suddenly started doing it.
Days went by and my friends kept telling me stuff they found out about it like they said that it sometimes happens and sometimes doesent etc.
Today my friend told me that it was all a joke and he wrote the letters TM on his BB status when he was Stoned and he tells me that it is my fault for bringing the whole conversation of TM up, even though I just mentioned it and then he starting making it bigger and worse.
He also told me that he got my friends in on it and they eventually encouraged me to make a video about the TM virus on youtube, humiliating myself further.
He tells me I need to get a joke, but when you have more than just 1 person doing the whole thing, it makes me feel as though the whole world is against me, I felt as though they were all laughing behind my back.
Also I have been lied to countless times in the past by other people and that has made me feel as though I am being picked on even if it is a joke.
Yet he remains adamant that it is my fault for bringing the whole thing up…
So who is to blame?