Starfinder: Firefly Arachnid

Chris Van Deelen

Firefly Arachnid Combatant CR 4 XP 1,200

Neutral Large vermin

Init +8; Senses: Darkvision 60 ft.; Perception +10


Defense                                                             HP 50

EAC: 16; KAC: 22

Fort: +8 (+18); Ref: +6; Will: +3

Defensive Abilities: DR 4 / -, hardened survivor; Immunities: electricity, fire, poison, radiation



Speed: 50 feet

Melee: Claw +12 (1d6+8 S Crit bleed 1d4) or bite +12 (1d4+8 P & F), or tail +12 (1d8+8 P Crit inject larva)

Space: 10 ft., Reach: 5 ft.

Offensive Abilities: Plasma Blast



Str +4; Dex +4; Con +1; Int -; Wis +0; Cha +0

Skills: Acrobatics +15, athletics +10, stealth +15

Feats: Improved initiative

Other Abilities: Larval injection

Languages: None



Environment: Any

Organization: Solitary, pairs, small groups (1d4+2), medium groups (3d4+3)


Special Abilities

Hardened Survivor (Ex): The firefly is completely immune to poisons and radiation, and it is able to withstand extreme conditions, even utter vacuum. Whenever the beast must make a saving Fortitude saving throw when dealing with environmental conditions, it gains a +10.

Larval Injection (Ex): Upon a critical strike with its tail, the firefly will inject 2d12 larva into the body of the victim. The target is allowed a Fort save (DC 13). This is similar to a disease, and it can be cured as such, but each day the victim is allowed another save. If it fails, the victim will suffer 1d4 points of permanent Constitution damage. The larva are destroyed if the victim is able to make 3 saves in a row, but each time the victim fails, the victim will have to begin again. When the victim’s Constitution reaches zero, it dies and the larva will burst free in 1d12 rounds after death. If the victim makes three saves in a row, then the lost Constitution will return as normal. If the larva escape, they will grow into full adult size in only 1d6+4 days.

Plasma Wave (Ex): Once every 3 rounds the Firefly is able to produce a wave of superheated plasma energy. It has a width of 15 feet and is 30 feet in length. This plasma wall will travel at 120 feet per round until it hits a barrier such as a wall or other obstacle. It will travel for 3 full rounds, after which it will dissipate into harmless vapors. This wall will inflict 2d6+4 points of Fire and Electrical damage, and anything caught in the wall is allowed a Ref save (DC 15) for half damage.

This particular version of the Arachnid species is quite different from the others. First, it appears more scorpion-like and has some resemblance to the actual Scorpion arachnid. Secondly, it this covered in very thick, green scales, making it all that much more difficult to damage with physical attacks. Instead of six legs, the creature has only four, and as such it can only make a single claw attack per round. It has a nasty bite, but what can make it even more deadly is the tail. On a critical hit, it can inject larva into the body of the target.

This ability also sets it aside from other arachnids, as other than the breeder, this is really the only type that is capable of reproducing without the need of the breeder or chooser. Although it is rather easy to get rid of the larva injected into the host, if they do not have access to proper medical equipment or a way to cure disease, the larva will eventually kill the host and emerge from the body.

Also, unlike many of the other Arachnids, these approach combat from a different perspective. They are hunters, and rely on ambushing their prey. They are not adverse to lying in wait until the right opportunity arises to strike. If working in pairs or even larger groups, they like to set up pincer ambushes, where they will catch unwary prey in narrow corridors or choke-points. If such areas are available, they will use their plasma wave in unison to deal incredible amounts of damage to their targets. Since they are immune to their own plasma (and all plasma generated by other Arachnids for that matter), they have no fear of being caught in the wall of plasma generated by others.

If by some miracle the prey survive the plasma waves, they will close and strike with their tails first, and then bite or use their claws.

Starfinder Creature Index

Chris Van Deelen is the creator and contributor to over half of the Wisdom from the Wastelands series, contributor to the Swords of Kos: Hekaton anthology, and the recently released 'Swords of Kos: The Rite'. He also wrote Creatures of the Tropical Wastelands, and 100 Oddities found in a Car. As prolific as he is, Chris Van Deelen continues to write and produce material which will be in publication soon. Not only is he a prolific content creator, he also has a wide selection of fiction and stories! If you like his work, please follow his personal author page on Facebook and on Twitter to keep up with his latest news and game content.