Was my food interfered with by pissed off waiter?

:(after complaining to the staff and manager in a well known and respected Dublin cafe i recieved my order with a very suspicious garnish!! it was a Sunday at 12.00 and I was rather hungry and probably a bit narkey and was looking forward to nice poached eggs and the works but was told I was a couple of minutes too late to order from the breakfast menu-which was fair enough.
When my gourmet BLT arrived sitting on top of the green garnish was an usual brown thin wafer thing, it tasted yuck and when I asked what it was the waiter didn't know but said he would ask the chef, a moment later the manager that I growled at earlier came down and asked what the problem was, I repeated the question and after studying the object he went to consult with the chef, on his return he was very apologetic and said that it was used to make the pasta paste and shouldnt have been used on my dish. At this stage I got rather suspicious and wondered was it payback for complaining --the object looks like something you might find on underside of your shoe, so I took a photo of it and wrapped what was left of it in a tissue.
I'm looking for your advice and comments please- should I get it analysed?-should I approach his boss? -I would hate to think this guy got his kicks out of a complaining customer eating a foreign object!!