"The Telescope Terror"
The gang overhears a conversation about some strange things going on at the local observatory. They head on up to take a look and discover some strange clues and a monster that chases them. But the gang turns the tables on the monster and captures it to find out that it is one of the scientists. She was trying to scare off the others so she could have more time to study what could be the oldest galaxy discovered by a scientist.
"The Night Marchers"
By Michael Kraiger and Scott Neely.
The gang's Hawaiian vacation is cut short with a mass ghost sighting near the condos that they are staying in. The gang goes out and exposes the ghosts as locals who are trying to keep developers from building more condos on sacred land. The gang goes along with them in order to convince one of the developers to change the location of his building project.
"The Night Marchers" is reprinted in Scooby-Doo, Where Are You? (2010) #47.