Bound Soul

Shapechanger. The Bound Soul can use it action to polymorph in to any physical creature with a CR of up to 1/2. The Bound Soul uses the Stat block of the creature it polymorphs in to, it reverts to its spectral form if it dies.

Magic Resistance. The Bound Soul has advantage on saving throws against spells and other magical effects.

Spectral Form. While the Bound Soul is in its spectral form it can't be seen or heard by anyone other than its its master and is immune to physical attacks, it can only be damaged by magical attacks. The Bound Soul is able to pass through physical and non magical object such at walls, floors, creates...The Bound Soul can be revealed by magic that show invisible creatures.

Familiar. The Bound Soul can serve another creature as a familiar, forming a telepathic bond with its willing master. While the two are bonded, the master can sense what the Bound Soul senses as long as they are within 1 mile of each other. While the Bound Soul is within 10 feet of its master, the master shares the Bound Soul Magic Resistance trait. The Bound Soul can only be released from its master by either one of them dying or by the will of the Bound Soul's master.

Chilling Grip (5/Days). While the Bound Soul is in its spectral form it can't wrap is ghostly arms around a creature, that creature must make a Wisdom Saving Throw DC 15. On a fail the creatures takes 4d6 Cold Damage and can't regain hit points until the start of the Bound Soul's next turn. On a success the creature takes half the damage. Until then the creature has an unnatural chill and appears pale.

Haunt (1/Day). One creature of the Bound Soul's choice within 20 feet of it must succeed on a DC 10 Wisdom saving throw or suffer one of the following effect of the Bound Soul's choice

1) frightened for 1 minute. The target can repeat the saving throw at the end of each of its turns, with disadvantage if the Bound Soul is within line of sight, ending the effect on itself on a success.

2) Short-Term Maddness for 1 minute. The target is subjected to an effect from the Short-Term Madness table.

3) The target suffers the effect of the suggestion spell.

When this is used creatures nearby can hear a whisper in the wind as the Bound Soul says "Boo"

Invisibility. The Bound Soul magically turns invisible until it attacks or uses Scare, or until its concentration ends (as if concentrating on a spell). Any equipment the quasit wears or carries is invisible with it.