Obligatory mobile postal sorry for any typos also you're in for a long one so there is a TL;DR at the end

This is from a year ago and I want to preface the post with this. My friend is a nice smiley guy who doesn't do stuff like this normally and I'm still friends with him and nothing has happened between us since.

So, we were out at McDonald's (4 of us) and we'll call my friend C.

C, me and two other friends are out getting a burger, fries and a drink. We finish up but I'm a bit slow so I just took the last half of my fries and nearly my whole drink out with me and everything is fine. We are on our way to the bus stop and all of a sudden C decides to smack my drink out of my hands. Okay that was really annoying and I ask him why the hell he did it. He said he thought it would be funny and I just got pissed of and left it at that,i reach for my fries and Whack he smacks them too. I get up with one of my friends and just go and get another fries and drink from the kfc we were next to. I have the idea to get a sachet of ketchup and go to get a little on his arm when I've gotten my food. 

So, I went outside and snuck up behind C whe he was talking to our other friend and got a blob about the size of a ring pull (the bit you pull on a can) on his arm. 

I ruke him as I was leaving and don't know what happened to the hoodie but as I said this was over a year ago and we've apologised and moved on (obviously) so, AITA

TL;DR friend hits fries and drink out of my hand so I get ketchup on his £30 hoodie as revenge. 

