Since my game has unusual characters, I want to have unusual monsters. The Jart is just one of many strange beasts they encountered.
Jart
FREQUENCY: Rare 
NO. APPEARING : 1-1,000
ARMOR CLASS: 9
MOVE: 24"/6"
HIT DICE: 1, 1 hp.
0/0 IN LIAR: 0%
TREASURE TYPE : None
NO. OF ATTACKS: 1
DAMAGE ATTACK: 1 hp.
SPECIAL ATTACKS: Swarm
SPECIAL DEFENSES: Not subject to mind control, charm, etc.
MAGIC RESISTANCE : Standard
INTELLIGENCE: Low
ALIGNMENT: Chaotic evil
SIZE: Small (4" inches)
PSIONIC ABILITY: Nil
Attack/ Defense Mades: Nil
These creatures are clearly constructs resembling birds. They have one green eye which glows at night. The beak, tail and tips of the wings appear to be some sort of thin metal, while the rest of the Jart feels like paper.
Jarts have a peculiar means of flight. They cannot fly higher than 12 feet from the ground and will not come within 5 feet of another Jart or a barrier. The ground must be rock, dirt, mud, etc. They fly between trees rather than over them. They cannot cross water deeper than 10 feet. Individuals fly very fast and are very maneuverable. A swarm of Jarts moves very slowly despite their individual maneuverability. They also avoid smoke, fire, clouds and fog. A Jart struck by any source of fire or heat will burst into flames. Jarts do not get saving throws vs. fire. Hitting an individual Jart with a missile or thrown weapon is a called shot and is done at a -4.
All encounters start with just one Jart, unless a swarm is already in progress. Jarts always attack last in the round. The initial Jart will attempt to "taste" a target, which requires a to hit roll. This does one point of damage. Once the Jart has a sample of the target, it will leave the area as quick as possible. Sampling or tasting allows the Jart to track that creature for 2 hours without error. Withing 1d6 rounds, the Jart will return with more companions. They will attempt to taste all creatures in the area, ignoring the first creature sampled. The number appearing will be equal to the number of humanoids and animals.
Once all targets have been sampled, they will again leave for 1d6 rounds. At the end of this period, roll a percentile die.There is a 25% chance that a swarm of Jarts numbering up to 1000 will appear.
A Jart swarm covers an area of 36" in game scale. Jarts do not like to enter structures do to the tight spaces, but can enter open spaces like barns or other large structures.
Characters who have been tasted or sampled inside the swarm will be attacked once per round for 1d6 points of damage. Due to their odd swarming pattern, characters may save vs. breath weapon for half damage.
Characters who have not been sampled will be sampled by the swarm. An attempt to sample a character will only occur once per round and only at the end of the round, which causes a one round pause in attacks. Characters will note that the swarm will cease all attacks in the round after a sampling and the whole swarm will pull back for that round to communicate with itself. There is a 50% chance that the swarm will leave at this point.
When a character uses a weapon on the swarm, any weapon including fists and missiles, it will do maximum damage every time as they are hitting more than one Jart per round. If a character is completely surrounded, all attacks are at a +4. Lit torches will do 1d6 points of damage per round and prevent the swarm from attacking the wielder. Fireball will destroy three Jarts for every point of damage rolled. A lightning bolt in the swarm will have a globe effect, like being used under water. This also does double damage to the swarm (but not to other creatures). Magic Missiles also have a curious effect on them, they do double damage and will destroy one Jart per point of damage rolled. The Magic Missile will also open a path through the swarm for one round.
If a swarm takes more than 200 of damage, they will retreat and regroup. There is a 25% chance that they will give up pursuit. If not, they will fly away from the area for 1d6 rounds before returning. If more than 400 points of damage occur, the swarm will attempt to flee.
Jarts must remain within 12 feet of rock or dirt to fly. However, they cannot get closer than 2 feet to any object. Jarts have no ability to crawl, swim or walk. This may create strange situations where the they cannot pursue creatures up trees or up wooden stairs, ropes or ladders, but can chase people up hills or up stone stairs. Jarts cannot cross water deeper than 10 feet. They have trouble entering windows and partially closed doors. Jarts will avoid nets, ropes, and other structures that could allow them to be captured. They can only be captured by tricky or magical means. This will never occur by accident.
Should one be captured, it will crumble like dried paper in 24 hours. If Find Familiar is cast on it within this time period, it will fall under the control of the spell caster and will take instructions. Instructions are limited to follow, find a person, or rest. If issued the order "Find", the Jart will search a six mile radius and return, successful or not. It can then lead the caster to the target if it was found. There is a 1 in 20 chance the Jart will run afoul of something that can destroy it while searching. The magic user will be aware of this, but will not know any details of the destruction. The Jart is not actually a familiar and there is no consequence if it is destroyed.
XP is awarded only if the swarm is driven off or destroyed. The XP value of the swarm is 400 for being driven off and 1000 if the whole swarm is destroyed. If a swarm appears, but leaves instead of attacking, the award is halved to 200. Catching one is worth 100 XP and casting find familiar on one results in 200 XP award.
