New class: Mindworm

To establish an otherworldy feel in my campaign I have decided to include unusual and alien classes! The Mindworm is a parasite similar to the pests of Alpha Centauri and the Valen from Burning Empires. However, I would like input on balance issues, better flavor and similar!
Prime requisites: INT & WIS
HD: as host or 1 hitpoint
Maximum level: ?
Mindworms are maggotlike beings between 6 and 12 inches long. They usually reside inside the brain of an enslaved host creature. Mindworms are curious and social beings and enjoy living in foreign communities and learning foreign customs although most societies treat them with hatred and fear. The mindworms curiousity extends to the arcane and most mindworms learn a spell or two during their lives. A mature mindworm will often establish a hive and attract fellow worms into it to find a true mate and spawn a new brood.
Of the starting attributes only INT, WIS and CHA are those belonging to the mindworm, STR, DEX and CON are all derived from the starting host body, a human.
Infesting a new body the mindworm drills its way into the brain of the new host via the ear. This does no damage to the host as the worm is very gentle. Bleeding and pain is to be expected though. The worm gains control of the hosts body if the following conditions are met:
*the level of the mindworm is greater than or equal to the level or HD of the host
Failure to meet this criteria means the mindworm is repelled by the body and brain of the host. If the HD of the host is unknown and the worm tries it usually notices failure when halfway in. Awkward if the host wakes and can do something about it!
*the mindworm has a higher INT and WIS than the new host
The mindworm lies snuggly between two lobes but fail to control the host because either brain or soul is too strong for it. It can crawl out at will. The host is most likely aware of the worms presence.
When leaving a host the host must save vs. death or be instantly reduced to 0 hitpoints.
If the host dies the mindworm does too. Jump ship if your host is in trouble! The soul of the host still lives (but is cowed) and restoration or restore life & limb cast on the host kills the mindworm. Energy drain effects both the mindworm and the host. Restoration and restore life & limb doesn’t kill a mindworm if the mindworm is the intended target.
The mindworm can use natural abilities of the host but not those dependant on knowledge (such as spellcasting).
The host must have a physical brain to invade.
Attack & saving throw progression: as their host, without host they fail all their attack & saving throws
Movement: as their host, without host very slow (1’) crawling or tunneling (through soil), they can breathe blood but not water
Spell progression: as a mage of half its level.
At 9th level it can establish a mindworm hive which is a fortified and hidden base inside another settlement.
What XP is balanced? Somewhere around 4000? To my mind they are not more powerful than spellswords because of their halved spell progression but they have the benefit of ridding themselves of wounds by changing body as well as stealing natural abilites of monsters they possess. Cool level titles? I imagine the hive will function similar to a thieves guild with the mindworms sent away on hijinks although modified such as to capture new hosts for the larvae. Should they be able to research new spells and make magic items? It would be very cool to have them reach some sort of butterfly stage at level 10 or so and just be birthed from the skull of their host. What would the advantage of being a butterfly be apart from flying and being fertile?
Ruling on how to handle this thing and stealth! It is obviously very small and quiet but it is also very slow.
Racial language: Wormtongue?
No telepathy!
Sleep is an obvious starting spell for most unless they have helpful adventurer friends.

Level titles:
Larvae, nymph, infiltrator, skull guest, dominator, caterpillar, brainseeker, earwig, possessrr, willbender, souleater, subimago, imago
Which are coolest? Some are parallells to butterfly stages while some follow the normal tradition of just describing what a pulp fantasy author would describe an individual of the class as.
Class proficiencies:
Alchemy, Alertness, Art, Contortionism, Arcane Dabbling, Ambushing, Black Lore of Zahar, Blind Fighting, Combat Trickery (incapacitate), Contemplation, Disguise, Diplomacy, Eavesdropping, Fighting Style, Illusion resistance, Language, Lip reading, Elementalism, Knowledge, Mimicry, Prestidigitation, Quiet Magic, Sensing Power, Tracking, Transmogrification, Trapping, Unflappable Casting, Wakefulness, Weapon Focus, Weapon Finesse
Trying to aim for a feeling of someone who is not 100% comfortable in their body (no +1 initiative proficiencies) and not caring about taking care of bodies since they are disposable (no animal husbandry or healing).

Obviously the 8th level title should be: conqueror worm.
Template: Body snatcher
Proficiencies: Ambushing, Combat Trickery (incapacitate)
Starting equipment: Mace, sap, leather armor, bola, backpack, lantern, 2 flasks of common oil, manacles, boots, wool wrapped around head to cover unhealed entry wound, hood to cover wrap, 2 weeks iron rations, 50 gp
This template represents a young worm with a newly caught fighting man who possess the tools and skills to ambush and get a new host in a direct, violent way.

Upon reaching 9th level (Imago), a mindworm may form a hive inside a settlement of other creatures. A hive is usually a well hidden, often underground, fortification but sometimes they are hidden in the open and pose and temples with aggressive recruiting. When words in the secret mindworm language gets around about the new hive being established it will attract 2D6 potential mates of 1-6th level with hosts to match. When a true mate is chosen all other mates will leave and each month countless 0th level mind worms are spawned. They are weak, fragile things and need help being inserted into (0th level) hosts before growing into intelligence. As long as the Imago provides food and safety they will be very loyal and willingly give their hosts lives for the safety of the hive.

This is mint, good stuff wilmer :slight_smile: