Butterfly nets have been used several times during the comics. When the category was created there had been two incidences within a month an three within a year, but it has also been used previously. The interesting part is that so far it seems the net has never been used to actually catch butterflies.
Here is a list of what they have been used/suggested to catch:
- 1110: Click and Drag: A radio-controlled helicopter
- 1193: Externalities: Unaware CMU graduates
- 1243: Snare: An international space station; (butterfly net like contraption named, but not shown)
- 1523: Microdrones: Microdrones; (butterfly nets discussed, but not shown)
- 1622: Henge: The setting Sun
- 1635: Birdsong: A songbird
- Thing Explainer: A soccer football in the explanation about Playing fields. Although it is stated clearly that this is not allowed they do exactly this in a soccer game on top of the Hole-making city boat (i.e. oil-rig).