After transporting the brave kids onto the alien spaceship to rescue Wimpy, they land in Africa, and then use a time travel thing to send the aliens back in time to live on Earth in dinosaur times, on the condition that they don't change anything and find somewhere else in live within ten thousand years.
"Most kids are afraid there might be a monster in their closet."
So, by being afraid of her closet, Cindy opened a fear portal into a land called Centrae. An elf boy helps her find her way while she waits for her friends to rescue her. The others show up in time to help Cindy and elf boy sort out some turmoil involving evil beings who can only be defeated by being laughed at, then they all go home.
Spooksville #23 - Phone Fear
"The gang did not understand who or what was calling."
So, Bryce, this candyass kid with a cell phone, starts getting crazy calls telling him to do stuff that he's obvs not gonna do, like burn down his mail carrier's house. The caller is named Nernit. Watch leaps to the conclusion that it's actually spelled "Neernitt" and it's the Internet calling. OMG - the internet is after us! I guess after everything else I've accepted from Pike, I can't start nitpicking now.
Neernitt has an army of followers who hold Watch, Bryce, and their friends captive until they agree to build Neernitt a body. Being the internet is cool and all, but moving around is apparently better.
Watch - I dunno - makes a body out of a robot friend he had who died in an earlier book, and then rigs it to trap Neernitt inside it once he puts his - I dunno - mental prowess into the body.