10 Tiny Star Trek Details You Might Have Missed The First Time
2. Livingston The Jellyfish - Genesis
This entry is inspired by Reddit user transwarp1, who correctly spotted that another creature on board the Enterprise-D fell victim to Barclay's t-cell virus in the seventh-season episode Genesis. While the story is a little silly, it nevertheless shows the actors getting a chance to have a bit of fun - including Jonathan Frakes, who gets to flip the bird to Picard, Data, and the audience, as he appears in a de-evolved, caveman state.
However, he is quite justified in being annoyed. Picard and Data have interrupted him attempting to get his lunch. He is attacking Picard's fish tank. Inside the fish tank, where Picard's Lionfish, Livingston, normally resides - there is now a floating Jellyfish instead.
The Lionfish has also contracted the virus, de-evolving to this gelatinous state. It is a slight spoiler for what awaits poor Spot the Cat/Iguana mere minutes later, though at least in her case, her kittens hold the key to reversing the effects of the virus for all sufferers on board.
This small detail. so obvious when it is pointed out, is actually such fine attention to detail, without hanging a lampshade on it, that it truly displays just how closely director Gates McFadden was checking that we were all paying attention.