Dragonfly

Dragonflies are surface critters with a fussy checklist. Daytime only, and the wind has to be calm. Inside a town they appear only while it is raining, and outside a town only while it is not. On top of that there has to be a cattail within roughly a screen of the tile the game picked, and the dragonfly gets moved onto that cattail when it appears. That is why you sometimes watch one pop into existence right in front of you instead of finding it already there.

The tile the game originally chose decides the variant, not the tile the cattail is growing on. Sand gives black, orange and yellow. Plain or mowed grass gives blue, green and red. A red one can therefore end up perched on a cattail rooted in sand, as long as there was grass nearby to seed the spawn. A Gold Dragonfly can replace any of them on a rare roll.

Any Bug Net works, but speed is the problem. A fleeing dragonfly keeps building velocity and ends up leaving behind a player wearing Hermes Boots or anything built out of them. Do not chase from a standing start, get moving first and close the gap with momentum you already have. Ones produced by a Dragonfly Statue cannot be caught at all and vanish in a puff of smoke the moment the net reaches them.

Clear out every cattail in the area except one, then stand about fifty tiles to one side of it. That puts the spawn area off screen while the cattail itself stays on screen, so the dragonflies materialize somewhere you can actually reach them. Draining the water does not kill a cattail, and dry ground stops water critters competing for the same spawn slots. A tall wall at the screen edge keeps other enemies from wandering in and despawns them, and a roof over the cattail stops your catch flying off before you swing.

A caught dragonfly can be carried around and let go again, or turned into an animated jar for a wall. Building the jar is a one way trip unless you throw it back through Shimmer. In Remix and Zenith worlds the height requirement is dropped and they can turn up at any depth.