Question on using Spiritomb Ticking Terror and switching.

Brandonusofa

Hello.

Spiritomb 89 Ticking Terror says "Until the end of your next turn, the Defending Pokemon's Weakness is now DARK.

If my opponent switches on their turn does that mean the new active is weak to dark?

or

If my opponent switches does that mean it's still weak to dark even though it's now on their bench?

or

does the act of switching undo Ticking Terror and no one is weak to darkness anymore?

Thank you friends. Happy July 4th to you all.