Spellcasting. The Accordion Deer is a 15th-level spellcaster. Its spellcasting ability is Intelligence (spell save DC 15, +7 to hit with spell attacks). The Accordion Deer has the following bard spells prepared:

Cantrips (at will): dancing lights, mage hand, minor illusion, thunderclap, vicious mockery

1st level (4 slots): bane, dissonant whispers, tasha's hideous laughter

2nd level (3 slots): crown of madness, hold person, shatter

3rd level (3 slots): fear, hypnotic pattern, stinking cloud

4th level (3 slots): confusion, dimension door, polymorph

5th level (2 slots): mislead, synaptic static

6th level (1 slot): eyebite, otto's irresistible dance

7th level (1 slot): regenerate, symbol

8th level (1 slot): feeblemind

Accordion Whack. Melee Weapon Attack: +2 to hit, reach 5 ft., one target. Hit: 2 (1d6 - 1) bludgeoning damage, or 3 (1d8 - 1)

Countercharm. Accordion Deer uses musical notes to disrupt mind-influencing effects. As an action, it can start a performance that lasts until the end of its next turn. During that time, it and any allies gain advantage on saving throws against being frightened or charmed. A creature must be able to hear it to gain this benefit. The performance ends early if it are incapacitate or silenced or if it voluntarily ends the effect (no action required).

Bardic Inspiration.

Accordion Deer can inspire itself or allies through stirring music. To do so, it uses a bonus action on its turn to choose either itself or an ally within 60 feet of it who can hear it. That creature gains one Bardic Inspiration die, a d12.

Once within the next 10 minutes, the creature can roll the die and add the number rolled to one ability check, attack roll, or saving throw it makes. The creature can wait until after it rolls the d20 before deciding to use the Bardic Inspiration die, but must decide before the DM says whether the roll succeeds or fails. Once the Bardic Inspiration die is rolled, it is lost. A creature can have only one Bardic Inspiration die at a time.

Accordion Deer can use this feature a number of times equal to its Charisma modifier (a minimum of once). It regain any expended uses when it finishes a short or long rest.

The Accordion Deer can make 2 legendary actions, choosing from the options below. Only one legendary action option can be used at a time and only at the end of another creature's turn. The Accordion Deer regains spent legendary actions at the start of its turn.

Cantrip. The Accordion Deer casts one cantrip it knows.

Attack. The Accordion Deer makes one Accordion Whack attack.

Move. The Accordion Deer moves up to half its speed.

Teleport (Costs 2 actions). The Accordion Deer magically teleports, along with any equipment it is wearing or carrying, up to 120 feet to an unoccupied space it can see.