Butterfly Swarm

Butterfly Swarm is a status-modifier weather effect in Mewgenics that is mechanically identical to Firefly Swarm, granting all allied cats +2 Luck for the duration of the chapter. The only difference is visual: instead of fireflies, the arenas are filled with fluttering butterflies.

Edmund McMillen acknowledged the similarity in a dev blog post, noting that he drew the butterfly sprites specifically for this weather effect and wanted to find a way to use them. The result is a charming visual variant of an already-beneficial weather effect.

All strategic advice for Firefly Swarm applies equally to Butterfly Swarm. The +2 Luck boost improves critical hit rates, dodge rolls, drop quality, and all probability-based mechanics for your entire team. There is no downside or enemy benefit to manage. When Butterfly Swarm is active, play normally and enjoy the stat boost.

Butterfly Swarm can appear in any biome and is classified as an uncommon weather. Between Firefly Swarm and Butterfly Swarm, the Luck-boosting weather pool is reasonably large, making it one of the more commonly encountered beneficial effects.