The mimic spits out a Chicken Strip Dinner

I feed the mimic a dozen pack of gobstoppers

It dissolves them because it does not chew.

I feed the mimic a scroll of time stop

 The mimic spits out some stopped thyme. 

I feed the mimic the Infinite Improbability Drive

The mimic warps into a different probable timeline, then reappears with a extreme probability USB

I feed the mimic a bowl of ice cream with chocolate chips

It spits the ice cream and chocolate chips back at you and tries to wash its mouth

I give the mimic a bullet to the head for not liking ice cream

The Mimic accepts his fate, and a new one crawls in as a replacement 

I give the mimic a ring of plot armor

It spits out a red shirt of death.

I feed it a dragon egg

The mimic spits out some odd-looking scrambled eggs. 

I feed it purple worm poison 

It spits out a dragon omelette 

I feed the mimic Darth Maul’s lightsaber

The mimic spits up a half-chewed red StarFleet uniform. 

I feed the mimic the severed right arm of a freshly slain goblin 

It spits out the severed left leg of a anciently slain orc.

I feed it the severed left leg of a anciently slain orc.

The mimic spits out a fossilized orc leg bone. 

I feed it an old pair of leather pants 

It spits out a new pair of leather pants.

I feed it a mcguffin.

The mimic burps, spewing a chunk of acid all over your face. You are now blinded

I feed it Bullybasher's Gauntlets

 It spits out Thor's Hammer

I feed it Mjöllnir

It spits out a rip in the space-time continuum, because they are the same thing. 

I feed it Treebrother

Damn! Did I kill the mimic?

It mimic stays alive.

I feed the mimic a mimic.

The mimic spits out of a perfect replica of itself, confusing you on which mimic is which.

I feed the mimic a tube with wax in it