And now for something different
Some space fantasy twists on MM critters.
Proper Science Fantasy “space stirges:"
* “Puppet Masters” Switch the monster’s Con drain to Wisdom drain as well as adding the spell-like ability to cast Dominate Person has some interesting possibilities.
* “The Long Trip Home” The stirges have established a nest inside the biotechnological components of the ship’s hyperdrive. The FTL drive is now locked on and the crew will eternally streak through hyperspace until the stirges are exterminated and the components are healed. -- This version of the stirge doesn’t even require one to change the monster’s stats since the beast’s Con drain can be used on the hyperdrive.
* “Party Crashers” Some “energy” stirges clamped onto the power conduits of the crew’s airborne shuttle in mid-flight. The craft is losing altitude fast and it seems that pouring on the juice only makes the stirges fatter. -- Depending the ship rules one uses, the stirge’s Drain Attack will have to be modified to be applied to either the craft’s movement, energy or hull points.
And two examples using trolls and troll varients
*"Have You Got Your Troller's Card" Working the unstable underwater mines of Ocean Base Atlatifc is hazardous, but mindless work. Which is why scrags are perfect miners, until they revolt. The authories are not going to let anyone leave until things calm down, a great idea until the scrags figure out how to sabatoge the base and start having water flood the PC's sector. -- No modification is needed on the scrags (page 180, second column, the MM aquatic varient of trolls). Heck! the PC may even support the revolution, the point is that the scrags have made the PCs life hell beyond just a combat scene.
(edit: Part of the challenge in this scenario would be to halfway flood corridors so that scrags can keep their regeneration abilites.)
*"Deja Vu And Who Are You?" You are all on a base in the Antartic, when you get the message you have to save a couple of Swedes at another base. -- Give the troll a "reproductive" cycle such as Curse of Lycanthropy or Create Spawn and speed up the victim's internal transformation time to only 6 or less hours while outward appearces into a Troll form still take 24 hours. Now your team can feel the parinoia of the movie franchise of "The Thing."
With Tenchi Muyo and the elves of Spelljammer, we have decent examples of how forest lovers can travel space. Add with the small twist that dryads can use ANY tree as a teleportion point and you have a strange world of "advanced races" that use the Green as their base for technology, transporation and even a "ecocyberspace."