AlHazred

I always felt the best straight one-shot adventure published for Champions was the classic Island of Dr. Destroyer. Direct, fast-paced, plenty of action with a few good character moments. Available in PDF from the Hero store, very cheap.
 

I guess the first question I would ask is, Does the edition of Hero System matter to you? A lot of adventures have been published over the years for all editions, from Hero Games or other sources. I also assume that you play as part of a group, rather than just your friend and you. Would that be correct?
 
Assuming for the moment that edition is not an issue, I'm struck by your mention of your friend's fondness for Lovecraft/Delta Green. For that and other reasons, I'm going to recommend a scenario written by gaming great Allen Varney for Fourth Edition, originally published in Champions in 3-D as "Horror World." This is the purest embodiment of Lovecraftian horror within the supers genre that I've ever seen, and IMHO fits very well into the "memorable" category. It's designed to be run in one (long) session or up to three shorter ones. Another big plus is that Varney got permission to host the entire adventure on his personal website for free viewing, retitled Anopheles: Atrocities From Beyond. It has detailed descriptions of the plot, setting, and full 4E stats for NPCs and foes. It lacks only the original artwork and drawn maps, which are in C3-D (which is available from the Hero Games website store for $7.50 in PDF): https://www.herogames.com/forums/store/product/625-champions-3-d-pdf-4th-edition/
 
If that doesn't work for you for whatever reason, I do have a few other things in mind in a similar vein. If you describe your concerns we can try again.

The Star-Devourer has stats for 2e/3e Champions. There's really only one character (the title monster) to convert.
 
A Lovecraft fan might enjoy it.
 
It's simple, full of atmosphere and can kill foolish PCs.

Derek Hiemforth compiled this list of all Hero System publications, under all regimes, through 2008. All the electronic books for 4E should be on it, and are noted as such.
HERO System Products List.htm
 
Note that most of them are now available from this website's store: https://www.herogames.com/forums/store/category/33-hero-system-4th-edition/

I got some use back in the day with The Big Little Book of Punch-Out Golems. It had perforated sections on every page, with unknown runes on both sides. If you put them together correctly ("Insert Tab Aleph into Slot Sothoth") the paper golem animated and would follow your commands. Unfortunately, it was made of the aforementioned paper, so it could be destroyed if it got wet, and it wasn't very strong. It could inflict savage, poisoned paper cuts, though!
 
There was an article in Dragon magazine issue #082, "Spells between the Covers" by Bruce Heard, which contains a bunch of magical tomes, such as Alterations of the Intrinsic Absolutes by Math the Magician and Ordinary Necromancy by Vecna.

I got some use back in the day with The Big Little Book of Punch-Out Golems. It had perforated sections on every page, with unknown runes on both sides. If you put them together correctly ("Insert Tab Aleph into Slot Sothoth") the paper golem animated and would follow your commands. Unfortunately, it was made of the aforementioned paper, so it could be destroyed if it got wet, and it wasn't very strong. It could inflict savage, poisoned paper cuts, though!
 
There was an article in Dragon magazine issue #082, "Spells between the Covers" by Bruce Heard, which contains a bunch of magical tomes, such as Alterations of the Intrinsic Absolutes by Math the Magician and Ordinary Necromancy by Vecna.

I got some use back in the day with The Big Little Book of Punch-Out Golems. It had perforated sections on every page, with unknown runes on both sides. If you put them together correctly ("Insert Tab Aleph into Slot Sothoth") the paper golem animated and would follow your commands. Unfortunately, it was made of the aforementioned paper, so it could be destroyed if it got wet, and it wasn't very strong. It could inflict savage, poisoned paper cuts, though!
 
There was an article in Dragon magazine issue #082, "Spells between the Covers" by Bruce Heard, which contains a bunch of magical tomes, such as Alterations of the Intrinsic Absolutes by Math the Magician and Ordinary Necromancy by Vecna.

Worked up for a Fantasy Hero thread, these are pretty nightmarish.
 
CAVEAT: They make use of packages I made up for other games and posted on the Boards. Your mileage may vary.
Hero Boards - Dwarf Werewolf Pirate.pdf
Hero Boards - Elf Vampire Ninja.pdf

Yes, I'm almost serious. Some of you may know Bruce McCall, an artist who appeared in many many magazines over the last 40 or so years. He makes some wonderfully whimsical pieces and I thought I'd share a few with you. Specifically, these would be of tremendous aid to anyone doing a Pulp/Anime style of game with large monstrous ridiculous vehicles.
 
I'll put each pic/description in it's own post, as otherwise, this will be one long sucker, and if it hoses halfway through, I don't want to have to retype it all again.
 
Okay, away we go.
 
The Caproni-Maroni C2 "Scud", sometimes called "The Instant Reversing Fighter" was a design anomaly. The sleek pusher/puller prop design was fast and strangely manueverable with the addition of the centerline ailerons. But its main claim to fame was the ability to reverse thrust at a moments notice (comparitively) and zoom off in another direction entirely. The designers did not wish to ruin the lines of their creation with any unsightly guns, so this unique ability proved more useful than might be thought.
 

Re: A black hole in orbit: what would it be like?