This crossed my mind today...
There is Schrödinger's cat and Newton's apple.
Are there any other famous animals/plants featured in physics in a similar way?
Arhytas made the first known steam powered toy in the shape of a pigeon, see The steam-powered pigeon of Archytas.
Priestley put a mint plant in a closed container with a burning candle. The candle flame went out after using up the oxygen, but after 27 days Priestley re-lit the candle, demonstrating that mint produces oxygen of its own.
Kekulé claimed, 25 years later, that he discovered the shape of the benzene molecule after having a dream of a snake biting its own tail. As with the apple, there are doubts that this actually happened.
Snake biting its own tail is an alchemic symbol called the ouroboros. It is sometimes also associated with Wallis's symbol for mathematical infinity (he did not make this association).
Pavlov's dog became a common metaphor for psychological conditioning after Pavlov's experiments with causing salivation in dogs by associating food with turning on a light bulb.
Asimov (who is a biochemist, in addition to the science fiction author) wrote a story about a goose that lays golden eggs, by transmuting oxygen-18 to gold-197 via an enzyme-catalyzed nuclear process. The goose can not reproduce due to heavy metal poisoning of the eggs, and a biopsy of the liver needed to uncover its secret would kill it. Asimov's riddle is to figure out how to make it reproduce (there is a scientific solution).
Parfit's “people who divide like an amoeba” illustrate a conundrum associated with brain transplants:
"My brain is divided, and each half is housed in a new body. Both resulting people have my character and apparent memories of my life. What happens to me?"
Jackson's Mary, the color scientist, who knows everything about the physics of colors, but grew up in a colorless room, sees a red tomato for the first time, and learns something new nonetheless. This illustrates the problem with explaining the so-called qualia.
A related earlier illustration is due to Wittgenstein, who imagined that everyone has a box where they keep a "beetle". That is everybody calls it "beetle", but "no one can look into anyone else's box, and everyone says he knows what a beetle is only by looking at his beetle". The point is to dispel the idea of a special non-physical entity, "mind".
Many of these sorts of things, featuring creatures or not, are what Mach called thought experiments, and there is extensive literature on them.
There's "Buridan's ass" in logic, which says that a "hungry donkey" will not be able to decide "between two completely alike bales of hay" (Duhem 2018 p. 13) and thus will starve. It's attributed to medieval physicist John Buridan (1295-1360), but a physics (not logic) version of it can be found in Aristotle's De Caelo 295b32 [375.]:
the man who, though exceedingly hungry and thirsty, and both equally, yet being equidistant from food and drink, is therefore bound to stay where he is
A good treatment of Buridan's ass can be found in Nicholas Rescher's Scholastic Meditations (ch. 1) or Studies in the History of Logic (ch. 7), "Choice without Preference: The Problem of Buridan's Ass".