Starfinder: Flammable Zombie
During the daytime these zombies appear to be like any other zombies – slow, shambling monsters on the hunt for meat to consume and flesh to infect. There is one aspect to these creatures that set them apart from the regular run-of-the-mill undead – there is a strange, green vapor constantly emitting from their mouths. Sometimes it appears as if they are breathing when in fact they are not.
Another aspect sets these apart from the typical undead menace that are encountered – they scream, and scream a lot! Most zombies will growl or groan, but these creatures cannot seem to keep their mouths shut.
Like most zombies, the sure-fire way to kill these is by destroying the head, which can be relatively difficult if not equipped with the right type of weapon. Still, inflict enough damage on the creatures and they can be taken down and the brains destroyed at a leisurely pace, but this again can be a dangerous proposition, depending on how many are encountered.