It spits up an amount of daggers equal to the sword. 

I feed it a Mimic's feast. Which is a hero's feast only for mimics

The mimic spits up 50gp to pay for the food, the mimic is thankful.

I feed the mimic Uranium 

The mimic starts polymorphing into SH'LURRRP'NG, the Mimics' God.

I feed him a lorry filled with LEGO figurines.

he eats your lorry full of lego figurines and spits forth a titanium chicken nugget.

I feed the mimic an angry bird

The mimic coughs and spits out an assortment of splintered wood, broken stone, and shattered glass, as well as three golden stars. Within the rubble is a frying pan that doubles as a mace of disruption

Feeling that the mimic is probably full of food, I open my decanter of endless water and spray a fountain of water into its mouth.

The mimic swallows all the water and then continues to eat everything in the room in an aggressive manner because it is insulted that you underestimated how much it can eat before it gets full.

I feed the mimic a Donaudampfschifffahrtselektrizitätenhauptbetriebswerkbauunterbeamtengesellschaft

The mimic looks confused at you, not knowing what you want it to eat. It then decides to eat you. Make a death saving throw.

I feed the mimic some yogurt 

1

 Looks like I died :(

Everyone gets 3 death saves.

The mimic loves the yogurt but, would of liked a spoon, it spits out a spork.

I feed the mimic, Mimicromicon The mimic book of mimics.

the mimic consumes the book and vomits forth a thousand dollar gold laptop.

I feed the mimic a million dollars and a shovel

It gobbles that stuff down and spits out an expensive coffin

I feed the mimic a mimic shaped birthday cake

But since no one knows what a natural mimic looks like, it is confused, and shoves you in the expensive coffin. 

I feed the coffin with you in it to the mimic. Make a death saving throw. 

The mimic does not like it when people feed it, other people. It looks disgusted at you.

I play the mimic the most cringiest KidzBop Song.

It eats it, spitting out the most cringiest KidzBop video

I get out of the coffin and feed the mimic 1 shiny coin

 The Mimic thanks you for the donation and spits out a potted cactus

I feed the mimic a top hat

The mimic puts on the top hat, and gives you a very good looking sword in return for making it look good.

I feed the mimic a crown

instead of eating the crown, the mimic puts the crown on top of the top hat. it gives you 900g for the crown
i feed the mimic D&D beyond

It spits out Fandom Games.

I feed the mimic its baby

The mimic spits out the baby.

I feed the mimic ice cream