Little black hose

It is the vent for your 12 volt battery. Your optima had a vent don’t know what you bought.

Try to address that rust if not it will eventually rot out and the bottom will fall out there’s a lot of weight on that area.
Few posters that had happened to quite a hassle to fix it.
It’s probably rotted under you spare tire too.

the water drips right on the hybrid battery fan connector too and rots it out.
That will throw a red triangle of death.

good times