Gold Water Strider

Water Striders already need a fairly specific setup before any of them appear, and the golden version only replaces one on a rare roll on top of that. Stack the two together and this ends up the gold critter most players never see without camping for it on purpose. A Lifeform Analyzer is close to mandatory, since it will flag one nearby, and spotting a small bug skating on the surface of a pool by eye is not realistic.

The three uses conflict, so pick before you catch it. Caging it gives you an animated piece of decor, but the moment it becomes furniture the critter is gone unless you run the cage back through Shimmer. Using it as bait burns it on a single fishing session, which is a waste when ordinary golden bait is far easier to come by. Selling it is what most people do, and given how hard it is to find a second one, hanging it on a wall is the sentimental answer rather than the efficient one.