"The Eternal Kingdom" achievement through friefly lanterns

For some reason my post got deleted two times already, even though it contained all new or detailed stuff. So here it is again:

You can catch fireflies with glass bottles and transport them somwhere else (IF they are actual entities). You can also craft an empty lantern: eight iron nuggets surrounding a bottle. The "fire" texture of the lantern will be replaced by a glass texture. You can than put up to three fireflies in one lantern manually, each adding 4 lightlevels to its radius. (Could also update so all lanterns work like that with candles, but thats probably tedious to actually play with.)

The achievement idea is as already stated the "The Eternal Kingdom" achievement which you trigger by placing a firefly lantern in one of the to-be-added deep dark cities. This would reference the lumafly lanterns spread all throughout the "eternal kingdom" of Hallownest from the AMAZING game Hollowknight.

Thats it, please stop deleting my post lol.

Also maybe firefly lanterns to feed and breed frogs or to put in potions, however that would kinda promote animal abuse, which is not something Mojang or I would want to promote, so maybe not.