'Enemy collisions along the x axis.  Removes enemy from enemy group
in order to check against all other enemies then adds it back.'

def check_enemy_x_collisions(self, enemy):

    enemy.kill()
    collider = pg.sprite.spritecollideany(enemy, self.ground_step_pipe_group)
    enemy_collider = pg.sprite.spritecollideany(enemy, self.enemy_group)
    if collider:
        if (enemy.direction == c.RIGHT):
            enemy.rect.right = collider.rect.left
            enemy.direction = c.LEFT
            enemy.x_vel = (-2)
        elif (enemy.direction == c.LEFT):
            enemy.rect.left = collider.rect.right
            enemy.direction = c.RIGHT
            enemy.x_vel = 2
    elif enemy_collider:
        if (enemy.direction == c.RIGHT):
            enemy.rect.right = enemy_collider.rect.left
            enemy.direction = c.LEFT
            enemy_collider.direction = c.RIGHT
            enemy.x_vel = (-2)
            enemy_collider.x_vel = 2
        elif (enemy.direction == c.LEFT):
            enemy.rect.left = enemy_collider.rect.right
            enemy.direction = c.RIGHT
            enemy_collider.direction = c.LEFT
            enemy.x_vel = 2
            enemy_collider.x_vel = (-2)
    self.enemy_group.add(enemy)
    self.mario_and_enemy_group.add(self.enemy_group)
