If your browser is still picking up trolling collectibles, you still have a chance of getting the troll, although, like all of the other collectibles positioned to the far right of the box, they are intended to be scarce. Downloading another browser or erasing your cookies in your present browswer would be extreme measures to take, but they could work.
The trolling collectibles all come from the "memebase" sites. I think I "found" the troll by going to Comixed, but I noticed that today the memebase collectibles were not coming up for me on those sites. That's a bit odd because as far as I know, there has been no announcement of their retirement.
Wow, Poopy dog is fantastic. Also, re: 'Tiger' - I left a comment under the LOL, but I want to repeat it here, in case you miss it (cuz I was that blown away!). THE BEST! I've seen many Tiger LOLz and that one has to be just the best! HUGS~