As Christmas approaches once more, Calvin receives a blast from the past when Earth's new alien owners, Galaxoid and Nebular, turn up to complain about the unexpected seasonal changes and demand redress.
This arc includes examples of the following tropes:
- Back for the Finale: The aliens are set up as oneshot characters, but they reappear once more in the last arc.
- Big Word Shout: Calvin yells, "No!" and "Bad idea!" when Hobbes decides to give the aliens their stockings.
- The Bus Came Back: Galaxoid and Nebular return after disappearing towards the end of the "Leaf Collection" arc.
- Call-Back: Calvin's deal with the aliens in the earlier arc forms an important backdrop to this one.
- Deadpan Snarker: When Calvin starts enthusing about the reward he'll get from Santa for his good deed, Hobbes snarks, straight-faced, that his unselfishness is an inspiration for the Christmas season.
- "Eureka!" Moment: Implied; Hobbes muses that they should do something to help the aliens stay warm, given that they can't do anything about winter. Calvin protests that it wouldn't work because their unusual body shapes would need something like huge socks. The next panel shows Hobbes removing stockings from the mantel.
- Glad I Thought of It: Galaxoid and Nebular complain about the cold Earth winter, demanding Calvin do something about it. Hobbes removes their Christmas stockings from the fireplace and gives them to the aliens, to which Calvin vehemently protests, since now "Santa can't fill 'em with loot!" Hobbes reassures him that Santa knows they did a nice thing and will work something out, to which Calvin replies, "Hey yeah, I did something good!"
- Hesitation Equals Dishonesty: Calvin's mother overhears him talking to someone at the door and asks who it is. After a couple seconds of scrambling for an excuse, Calvin lies that the aliens are Girl Scouts selling cookies.
- Hoist by His Own Petard: When Calvin's mom hears him talking to Galaxoid and Nebular, he lies that they're Girl Scouts selling cookies to cover up the truth. Unfortunately, Calvin's mom decides she'll buy some cookies, forcing him to shove the two indignant aliens away and slam the door.
- Plot Archaeology: Downplayed. In one storyline, Calvin needs to make a report on leaves, which he gets two aliens named Galaxoid and Nebular to make for him in exchange for ownership of planet Earth. He flunks, of course. Many strips (and a few out-of-universe months) later, when winter comes, Calvin gets excited to go sledding, when Galaxoid and Nebular show up at his front door, covered in snow and apparently angry over not knowing about winter being a thing on Earth. Hobbes helps by giving them his and Calvin's Christmas stockings to wear, which is all it takes to warm them up and placate them.
- Simple Solution Won't Work: When Calvin asks him how to handle the problem, Hobbes suggests he offer to refund the alien leaf collection they paid him last time in exchange for the planet. However, Calvin admits he threw out the project after it failed to earn him a passing grade.
- Single-Biome Planet: Implied; Galaxoid and Nebular see winter and snow as the result of a faulty axis that Calvin should have fixed before he turned the planet over to them, implying they expected a constant temperature.
- You Didn't Ask: Galaxoid and Nebular accuse Calvin of withholding the information that the planet undergoes winter. Calvin, having experienced winter his entire life, just answers that they didn't ask.
- You Get What You Pay For: In an earlier arc, Galaxoid and Nebular bought the Earth from Calvin for fifty alien leaves, which are implied to be worthless on their planet. A few months later, they come back to Calvin to complain about the Earth's tilted axis, to which Calvin replies "let the buyer beware".
