The Okiron Butterfly is an agent for both Creatures 3 and Docking Station.
They are classified as a bug and can be found on Eemfoo.org. They are perfectly safe to eat (highly recommended for Draconian Norns) and can be very beautiful fluttering about in your world.
In Docking Station, injecting this agent will create four of these butterflies in the upper level of the Norn Meso. It is highly recommended that you have plenty of plants available and growing, otherwise the caterpillars will have nothing to eat and won't change into more butterflies. If the number of butterflies drops below four, they will be recreated in the Meso.
Here's the description from TwilightCat's page: "A cute norn watches a butterfly of similar colors fly by... This butterfly is faster than the Inkras and is really hard to catch! Remember to have lots of plants around for these buggies! ^_^
See also the Inkras Butterflies and the Lensis Butterflies.