((For the sake of moving the fight/story along, I'm going to go ahead and go for Oban, and then add in Kwiz. Then, it'll be Rush's trurn.))

Oban runs 15' up from where he's at to flank the mimic to the South. Then, he's going to attack with his shortswords. 

Main Action: Attack: 7 Damage: 9
Bonus Action, two-weapon attack: Attack: 19 Damage: 1

((That first roll sucked...dang. The second roll was really good, but the damage sucked. le sigh))

((Now, we'll add in Kwiz's turn...))

Quote from kevtr0n >>

 ((it's about bed time here, so I'm going to queue up Kwisatz' turn))

Kwisatz looks towards it and gasps "Fastinating!" he says, and starts to pull out a sketch book, before realizing that it has hurt his companion. He instead does a small gesture with his hand as a skeletal hand floats from it towards the Mimic.

chill touch Attack: 9 Damage: 5 ((miss... ㅜㅜ))

From the back of the room, with a flourish of his hands, and a softly spoken incantation, Kwiz sends out a ghostly skeletal hand that reaches out for the mimic, but in his excitement at discovering this new-to-him monstrosity, he lost focus on the spell, and his chill touch did nothing.

Next up, Rush.

I should add that when the mimic changed out of it's "object form" into it's natural form, the boomerang fell off of it right in front of where it's standing.

Rush doesn’t draw his sword, instead holding for an amulet, which begins to ring out.

toll the dead DC 13 Wisdom save or take 3 necrotic damage

Mimic WIS saving throw: 4

Sael is up next! 

((For the sake of moving the story forward, I'm going to go ahead and go for Sael.))

Sael is going to use her Bonus Action for Second Wind and regain 7 HP.

Then, for her main action, she is going to swing her longsword with two hands at the mimic:
Attack: 18 Damage: 5

The mimic will go next.

 The mimic is going to target Rush with it's pseudopod attack: Attack: 6 Damage: 5

The mimic misses Rush.

It's Oban's turn, next.

Iban will take his action and bonus action to attack with his two swort shords 

action attack: Attack: 26 Damage: 10

bonus action attack: Attack: 22 Damage: 3

Oban rears back with both of his shortswords and in a well trained flurry, he lands both attacks, drawing blood. 

Next up is Kwiz!

I'll go ahead and post for Kwiz since he's visiting with family.

"Kwisatz will continue to use Chill Touch."

14 Damage: 4

Kwiz reaches out, and with a familiar flourish of his hands and a softly spoken incantation, Kwiz sends his ghostly spectral hand out to touch the mimic. The hand clearly sends chills throughout the creature.

The mimic has taken 4 points of necrotic damage and now has disadvantage on attacks against Kwiz.

Next up, Rush!

Rush draws his mace and swings at him

Attack: 18 Damage: 7

Rush, right after barely escaping getting hit with the mimic's pseudopod, used the momentum of his dodge and brought his mace around like a furious windmill of pain down on the mimic's head.

This creature is definitely feeling the beating it is enduring, but he's not out of the fight, yet.

Next up is Sael!

Sael rears back with her longsword and takes a swing at the mimic.

 Attack: 7 Damage: 4

Considering the damage Sael took at the onset of this fight, she's still feeling fatigued and struggling to deal damage, but she's still in the fight.

 Having just swung at it, the mimic bites Sael. 

Attack: 15 Damage: 4

Sael takes another 4 points of damage. Oban is up next! 

Sael is cursing the Mimic out while desperately attempting to consider her options.

two more swort shord atacks!! have at thee!!

Attack: 24 Damage: 8

Bonus action Attack: 6 Damage: 3

Oban swings wildly, again at the mimic, one of his shortswords making contact. The monster is now very badly injured. 

Kwiz is up!

mentally noting to himself "surprisingly sturdy. can alter shape. sharp teeth... ah!" as he casts another Chill Touch towards the creature.

Attack: 18 Damage: Unable to parse dice roll.

Kwiz reaches out his hand, whispers his incantation, and once again sends his ghostly apparition of a hand out towards the beast. The hand touches and with a cold fog coming off of the spot where the fingers of the hand made contact  with the skin of the creature. For a moment, the mimic seizes up, then it falls over. Dead. 

“Huh... a shape changer. I didn’t expect that.” Rush blinks.