Collage of Madness

Clerics channel magic from the divine, sorcerers live magic, wizard's study it, bards feel it. A Collage of Madness bard gets his magic from insanity. The chaos wracking one's mind materialized. This collage takes the insanity wracking a bard's mind and expels it, and evokes it in others. 

Song of Insanity

You can spill your madness into the mind of another at the cost of your sanity. At 3rd level, as an action, you can as an action expend one use of your bardic inspiration to awaken insanity in your opponent. They must make a wisdom saving throw (equal to your spell save DC) or they are affected by short term madness (page 264 in the DMG).

Whevever you use this ability (reguardless of if the target succeeds or fails the saving throw) roll your bardic inspiration die. You take psychic damage equal to the total.

This ability gets stronger when you reach certain levels in this class. At 6th level you can choose to inflict long term madness insted of short term, and at 14th level you can choose to inflict permenant madness.

Manifestation of Madness

At 3rd level, you express madness through your spells to frighten others.

You learn the thaumaturgy spell, if you do not already know it. When you make a charisma (intimidation) check, you can cast it as a free action to gain advantage on the check.

In addition, you can also cast Thaumaturgy as a free action when you cast a spell of 1st level or higher.

Madman's Glasses

At 6th level, you can shift the perception of others to a dangerous extent.

As an action, you can force one creature that you can see, and that can hear you to make a wisdom {{savedc:cha}} saving throw. If it fails, the target's vision is reduced to 30 ft. and any creatures within it's vision are perceived as hostile monsters. 

You can use this ability once per long rest.

Mind Shatter

Starting at 14th level, as an action, you can create a droning, deafening noise with your instrument.

If a creature is concentrating within 30 feet of you, the creature must make a successful Constitution saving throw against your spell save DC or lose concentration. Additionally, all creatures within 10 feet of you take 5d6 psychic damage. After you use this ability, you must complete a long rest before using it again.