I liked your story that hints at the idea that cats really do rule the universe. The ending caught me by surprise, and is almost the reverse of that Twilight Zone episode, "To Serve Man." Or in this case, to serve cats.
I think the story is charming and well thought out. You may also be happy (maybe not?) to know I am somewhat of a professional editor. I don't do it for money anymore, but for friends, I enjoy helping out. So if you'll pardon my jumping in, somewhat uninvited, I took the liberty of editing your entire story.
Of course, it's strictly up to you as to whether you incorporate the changes I recommend, but just in case you're curious to see where some of your weak points are, please review the following.
This is a case of making a good story into a great story. So I hope you'll accept my presumptuousness that you might find this interesting. See what you think and let me know if this was helpful and made sense. I also found the story to be very funny.
A teenager looking through his telescope discovers a new star.
In the headline above, a better form of a news headline might read:
Teenager looks through telescope and discovers new star.
Unfortunately, at that moment my pure bred Siamese cat, King Mongkut.
The sentence above is incomplete. I think you meant to say the following:
Unfortunately at that moment, my pure bred Siamese cat, King Mongkut, needed to go outside.
When I opened the door, I saw that it was snowing, so I placed my mug on the stand in the foyer, sat down in the chair, and put on the cowboy boots that were next to the chair.
Above, I changed "sit" to "sat".
I knew from the tone in his voice that I didn't have time to get my coat out of the hall closet, so I took my sister's silver mink coat off the tree in the hallway. Putting on the mink, I picked up my coffee and followed the cat down the front steps.
Please compare my version above to your original. I think the needed changes are pretty easy to see.
Anyway, I was standing on the front walk, sipping coffee, and watching Mong search for the perfect spot to relieve himself, when I heard a noise. At first, I thought it was the front door closing, but then someone behind me spoke.
I turned around to see who was speaking. There stood a three-foot-tall creature with grayish purple skin and huge, insect-like eyes.
Notice how the above one paragraph, is now three separate ones. The alien needs his own paragraph is the reason. Pay close attention to all the small changes compared to your original single paragraph.
"Yes," I smiled, thinking that one of the neighbors was shooting a video which would appear on YouTube in a couple of hours. "May I help you?"
Above, I added a comma after smiled.
I think it might be really cute to have the alien first try talking to the cat directly. What do you think? Or would that give things away too soon?
"Yes." I had to bite my tongue to keep from laughing because I had not intention of screwing up a video that could go viral.
Above, I put a period after "Yes." And changed "bit" to "bite".
"Good." The creature managed a big grin.
Above, I put a period after "Good." And capitalized "The".
"Uh..." I heard Mong yawl and then I lost consciousness.
Above, I changed "yawl" to "yowl". A better choice, I think.
When I came to my senses, I was sitting in a cot in a small windowless and doorless cell. Mong and another cat, a large female Maine Coon, were sitting next to me and looking very proud of themselves.
Neva, I have an 18-pound rescued Maine Coon who is more human than feline. Or is that, more alien? No changes needed above.
"Well," I said as I continued sipping, "at least I didn't spill my coffee when I blacked out." I looked around and wondered where I was.
Lots of small changes above. Please compare with your original. Thanks.
The wall in front of me slid open. "Good morning, Miss...?" said another grayish purple creature carrying a tray of food.
Above, note the period after "open". And the question mark after the ellipsis in Miss...? This allows you to answer in the next line.
The creature seemed to frown. "When we took Queen Moxie Gore, her teenage human was looking through a telescope.
Above, I put a period after "frown". It could also be written: The creature frowned as he spoke. "When we
Before we could capture him, he ran into his house, apparently excited over something."
Above, I added "apparently".
"OK," a panel opened in the wall next to the cot and a table emerged. The creature placed the tray on the table.
It's not clear what you're saying here. The creature gets its own paragraph, however, when he does anything. Do you mean, "OK," I said. If so, then the next lines all go on a separate paragraph as follows:
"OK," I said.
A panel opened in the wall next to the cot and a table emerged. The creature then placed the tray on the table.
"Uh," I just stared.
Above, the line reads better this way:
I just stared and only muttered, "Uh...."
Above, note the fourth period in the ellipsis, which means the dialogue just trails off.
"You wish a...job description? I think that is what you humans call it." The creature started toward the door and then turned around. "Miss Margo, your job is to care for Queen Moxie Gore, her mate, King Mongkut, and their offspring."
Above, I closed up the space in: a...job description? And added the question mark. Otherwise this reads fine.
Okay, that's enough out of me. Consider yourself thoroughly edited, and I hope it has some value for you.
** Image ID #1922401 Unavailable **