What is Christmas present Tohru gives Miss Kobayashi in episode 10?
This is just how anime shows "a very disgusting thing vaguely shaped and colored like this".  It's not a new thing, off the top of my head I can remember one other instance for which we have a question here: Why are there censored/retracted art when there is no problem and here's the video of that fragment. Also see this question and its answer: Why do they censor vomiting in anime?