Where can large water-dwelling mammals only dream of graduating from when they grow up?

Why do the watermelon and the honeydew melon have to have a wedding ceremony? Because they:

I make the heavens and earth quake, with glimmering blade and deafening roar, I leave naught but ashes in my wake, for the taller foes I yearn even more.

I roar and shout as I please, battling only the tallest and strongest enemies. My power is heard for miles on the breeze, yet until I attack I am unseen. My sword carries the brightest gleam, despite having never been sheathed.

I flicker soft in twilight’s grip, a tiny dancer on night’s lip. I wear a lantern on my back, to guide the dark along its track. Though not a star, I briefly shine, what am I? A tiny glow divine.