Mimicry is an resemblance between an organism and another object and they
advantages are???

Camouflage or deterring predators

Explanation: Mimicry can help an organism blend into its surroundings if they are resembling something in the environment.

It can also help deter predators if they are resembling a poisonous or venomous organism; an example of this is the non-venomous king snake, which mimics the venomous coral snake to deter predators from eating it.

1). Its advantages is defense adaption.

2). It makes them look like an uninteresting object.

3). It becomes a specie that potential predators normally avoid because it posses an unpleasant or harmful feature like a foul smell or taste, or a poisonous sting.

Note: Several insects look like dead leaves and bird droppings and so, although noticed, are ignored by their potential predators. Example is in Mullerian mimics, unrelated animals like the striped polecat and the striped weasel of the savanna have similar broad white stripes on a black body. Their enemies associate the conspicuous appearance with the foul smelling liquid they squirt, and so avoid them.

sheep is a herbivore animal whereas grasshopper belongs to the class chordates but both of them feed on greens.  

if grasshopper and sheep feeding on a pasture land, i do not think both of them will have any impact on each other. however, the number of the species can make difference. since sheep feed on greens, there is a possibility there left no pasture land for the grasshoppers or they may get extinct.