Creature Adjustments
The Starfinder galaxy contains innumerable creatures beyond those presented in this book, and you'll likely want to create custom creatures to fit the needs of your campaign. While you can build brand-new creatures using the guidelines in GM Core, sometimes you'll want to make small adjustments to an existing creature. Consider using the following adjustments to add thematic abilities or tweak a creature's combat power to better suit your campaign.
These changes are designed so you can apply them quickly, but they aren't comprehensive. You should review the adjustments and consider the specific application to determine if you're introducing unintended consequences, especially in terms of a creature's threat level in combat. For example, applying hardlight adjustments to a creature that already has several immunities or resistances to specific types of energy damage might result in a creature that the PCs have a difficult time hurting due to its many defenses— this could be exactly what your story needs, or it could lead to an encounter that's not enjoyable.
Elite and weak adjustments are the most basic ways to adjust a creature's combat power, and they work best with creatures that focus on physical combat. These adjustments overstate the normal numerical gains the creature would receive from increasing its level to make up for the lack of new special abilities. Creatures that cast spells or rely on noncombat abilities typically need specific adjustments to those spells or abilities. These adjustments have a greater effect on the power level of low-level creatures, as noted. Applying the adjustments more than once to a creature should be avoided. If you need to alter a creature's level more drastically, use the GM Core guidance on building creatures.
Be mindful that you don't overdo it with creature adjustments—players often enjoy recognizing and learning about creatures. If none of your creatures are recognizable, or all of them break the rules in some way, your players might begin to lose their sense of immersion because all the creatures they're encountering are strange or different than what they expect. On the other hand, if you're running an adventure on a strange planet or in a remote region of the Vast, it might be best if every creature has unexpected adjustments!