Insect Bloodline

Your magic comes from your relationship to some type of strange, arthropod-like creature. Perhaps you were the hybrid descendant of a drider or a thri-kreen, created as part of some grand design. Or perhaps yours was the result of a magical experiment, transforming you or your predecessor into a strange mixture of humanoid and insect. Regardless of its origin, you bear the physical marks of your ancestry, with exoskeletal armor and other, stranger features, and your magic, while powerful, is often reminiscent of your own insectile nature.

Insect Heritage

You choose one of the following types of arthropod as your ancestor. You gain features from them at 1st level, and again at later levels.

Ankheg. Your melee attacks do an additional 1d6 acid damage.

Drider. You have advantage on saving throws against being charmed, and magic can't put you to sleep.

Phase Spider. You can innately cast the spell Misty Step a number of times per long rest equal to your Charisma modifier.

Thri-Kreen. You have advantage on Dexterity (Stealth) checks made to hide. Additionally, you can choose whether to use Wisdom or Charisma as your spellcasting ability for your sorcerer spells.

Umber Hulk. You can innately cast the Confusion spell once per long rest. However, instead of being shaped as a sphere, the spell targets a single creature you can see within 30 ft.

Arthropod Form

Your insect nature physically alters you, as shown in the table below.

Ankheg. You gain proficiency with light and medium armor, and while you aren't wearing armor, your AC equals 14 + your Dexterity modifier (max 2). Additionally, your unarmed strike deals 1d6 + Str slashing damage, and your hit point maximum increases by 1 each time you gain a level in this class (including first).

Drider. You gain proficiency with light and medium armor, and while you aren't wearing armor, your AC equals 13 + your Dexterity modifier. Additionally, you have a climbing speed equal to your walking speed, you ignore movement restrictions caused by webbing, and you gain the following ability: Spider Climb. You can climb difficult surfaces, including upside down on ceilings, without needing to make an ability check. 

Phase Spider. While you aren't wearing armor, your AC equals 11 + your Dexterity modifier. Additionally, your unarmed strike deals 1 piercing damage and 1d6 poison damage, you have a climbing speed equal to your walking speed, you ignore movement restrictions caused by webbing, and you gain the following ability: Spider Climb. You can climb difficult surfaces, including upside down on ceilings, without needing to make an ability check. 

Thri-Kreen. You gain proficiency with martial weapons and light and medium armor, and while you aren't wearing armor, your AC equals 13 + your Dexterity modifier. Additionally, you learn the Mage Hand cantrip if you don't already know it.

Umber Hulk. You gain proficiency with light, medium, and heavy armor, and while you aren't wearing armor, your AC equals 16. Additionally, you gain a burrowing speed equal to half your walking speed, your unarmed strike deals 1d8 + Str slashing damage, and your hit point maximum increases by 1 each time you gain a level in this class (including first).

Enhanced Alteration

At 6th level, your insect heritage grants you additional benefits.

Ankheg. You add 1d6 acid damage to any damage roll you make. Additionally, you can spend 1 or more sorcery point to increase this damage by 1d6 for each sorcery point spent.

Drider. When you gain a level in this class (including this level), you can choose spells from the cleric spell list as well as the sorcerer spell list. Additionally, when you cast a spell as an action, you can spend 1 sorcery point to make one weapon attack as a bonus action.

Phase Spider. You learn the Blink spell if you don't already know it. Additionally, after casting this spell, you can spend 1 sorcery point at the end of each of your turns to change the result of the d20 rolled to a result of your choice, and while in the ethereal plane, you can spend 1 sorcery point at the beginning of your turn to stay there until the beginning of your next turn.

Thri-Kreen. When you gain a level in this class (including this one), you can choose 1 additional spell from the wizard spell list. Additionally, when you cast a spell as an action, you can spend 1 sorcery point to make one weapon attack as a bonus action.

Umber Hulk. You can choose to cast spells of the enchantment and illusion classes by spending a number of sorcery points equal to half the spell's level, rounded up, instead of expending a spell slot.

Metamorphic Magic

Starting at 14th level, you gain an additional Metamagic option in addition to any other metamagic options you have.

Ankheg. Vomiting Spell. When you cast a spell that targets one creature, you can spend 3 sorcery points to make it affect each creature in a 15-foot cone originating from you. Alternatively, when you cast a spell that targets an area of effect, you can spend 2 sorcery points to change that area of effect to a 15-foot cone originating from you.

Drider. Arachnid Spell. When you cast a spell that targets a single creature, you can spend 3 sorcery points to use a bonus action to cast the spell Polymorph on that creature. When cast in this way, you can only transform the creature into a spider or giant spider.

Phase Spider. Teleporting Spell. When one or more creatures you can see are affected by a spell you cast, you can spend one or more sorcery points. For each sorcery point you cast, you can choose to either teleport one affected creature up to 60 ft. in a direction of your choice into an unoccupied space you can see, or force one affected creature into the ethereal plane until the end of its next turn.

Thri-Kreen. Psionic Spell. When you cast a spell, you can spend 2 sorcery points to cast it without using verbal, somatic, or material components. You can use Psionic Spell even if you have already used a different Metamagic option during the casting of the spell.

Umber Hulk. Stunning Spell. When you cast a spell on a creature, you can spend 2 sorcery points to force it to make a Charisma saving throw against your spell save DC. If it fails, the creature is stunned until the end of its next turn.

Adult Form

At 18th level, your insect form reaches its final stage.

Ankheg. You gain immunity to acid damage. Additionally, you can spend 1 sorcery point to use your reaction to grant another creature you can see immunity or vulnerability to acid damage for 1 minute.

Drider. When you deal damage to a creature that is aware of you, you can use your reaction to spend 1 sorcery point and force the creature to make a Wisdom saving throw against your spell save DC. On a failed saving throw, the creature takes an additional 3d6 psychic damage and becomes frightened of you or charmed by you (your choice).

Phase Spider. When a creature makes a weapon attack against you, you can use your reaction to add your Charisma modifier to your AC for that attack. If this causes the attack to miss, you can immediately teleport up to 60 feet to an unoccupied space you can see.

Thri-Kreen. Whenever you make a weapon attack, you can spend 1 or more sorcery points to cast a spell of a level up to the number of sorcery points spent. The spell can only target either you or the target of the attack.

Umber Hulk. When you cast a spell on your turn, you can use a bonus action to spend one or more sorcery points. Your AC increases by an amount equal to the number of sorcery points spent until the end of your next turn.