The Butterfly outfit was a cosmetic reward from the Tribute to Guthix event released on 12 March 2013. All 3 pieces were obtainable for free from Memstix during the event, along with the Sword of Edicts and the Butterfly Dervish emote.
It has became available again during the 2019 Easter event from the same druids and Tribute stone that has appeared next to Falador Lodestone (similar to Tribute to Guthix event), however this time they do not provide the Butterfly Dervish emote and the butterfly event itself is different.
Memstix gave away all pieces for free for a certain period, in addition to the Sword of Edicts and Butterfly Dervish emote, warning that a time of imbalance is approaching.
It consists of 3 pieces: