Fairy Boots

This is the one recipe in the movement accessory tree that is a dead end. Spectre Boots feed the whole upgrade chain that finishes at Terraspark Boots, and folding them into Fairy Boots takes them out of that chain. You get the flower trail and the running speed in one slot, and you give up every tier above it.

If you want both effects, finish the boot upgrades first and treat the flower trail as something you live without until much later. If you already made the mistake, Shimmer breaks them apart again, so the loss is recoverable now in a way it was not when the item was new.