Middle clicking on entity (Mob) give "minecraft:spawn_egg 1 0".

On "middle-clicking" (mouse 3) on a entity (Mob) that give a "minecraft:spawn_egg 1 0".

Example: If I "middle-click" in a Zombie that give me one "minecraft:spawn_egg 0" instead of a "minecraft:spawn_egg 54".

P.S. : Sorry for my bad english, i'm french !