To be honest, I really liked this one! I thought the plot was a little creepy, but interesting. And I thought this episode was very clever. As for the ending with the closed sign, I don't see what the problem is with that. The writers didn't run out of ideas, the closed sign was part of a JOKE! It was part of the punchline! Think about it. After Krabs proved to be a selfish beast, Madam Hagfish made it look as if she had cast a spell to curse the Krusty Krab. She caused Mr. Krabs and Spongebob to become extremely paranoid, and little did they know that she just put a closed sign in front of the Krusty Krab, and that they were causing THEIR OWN bad luck! the punchline is, Madam Hagfish basically made them think that she put a curse on the Krusty Krab, giving it bad luck, and little did they know that she only put a closed sign in front and let them cause their own bad luck without even knowing it! If you think about it, it was actually a really clever (and hilarious) punchline and the I think the writers did a very good job at it. I think this episode is very underrated and it has more humor than people give it credit for. I think this is the best Legends of Bikini Bottom episode overall, and definitely the third best of Season 7!
10/10 :)