Laravel seeder - check if unique slug exists already

Question

I am seeding a database table ('games') from several csv files. The table has a many-to-many-relationship with another table ('consoles'). The code works for the first csv file...

I am expecting to encounter duplicates (one game may release on multiple platforms).

Rather than an error exception, I would first like to check if the record (unique slug) already exists within the database table, - if slug has already been used, just update relationships to existing record, syncing the pivot table against new console (I believe this is attach or sync?) - if not - create a new record.

The model/schema is setup as such:

<?php

use Illuminate\Support\Facades\Schema;
use Illuminate\Database\Schema\Blueprint;
use Illuminate\Database\Migrations\Migration;

class CreateGamesTable extends Migration
{
    /**
     * Run the migrations.
     *
     * @return void
     */
    public function up()
    {
        Schema::create('games', function (Blueprint $table) {
            $table->increments('id');
            $table->string('title');
            $table->string('slug')->unique();

...

An example seeder code is

use Illuminate\Database\Seeder;
use Illuminate\Database\Eloquent\Model;
use Illuminate\Support\Str;

class SnesGamesSeeder extends Seeder
{
    public function run()
    {

        // Fetch the data from our CSV File
        $data = $this->seedFromCSV(base_path('/database/seeds/csvs/snes-csv-filtered.csv'), ',');

        foreach ($data as $game)
        {
            $title = $game['Title'];
            $slug = Str::slug($title)
            $date = strtotime($game['release_date']);
            $format_date = date('Y-m-d',$date);

            DB::table('games')->insert(
                [
                    'title' => $title,
                    'slug' => $slug,
                    'release_date' => $format_date,

...

I would like to be able to do something like

   foreach ($data as $game)
   {
     $title = $game['Title'];
     $slug = Str::slug($title)
     **if(*** $slug already exists in 'game' table){
       (find ID) -> ->consoles()->attach(5);
     } else {**
       DB::table('games')->insert(
         [
           'title' => $game['Title'],
           'slug' => Str::slug($game['Title']),
           'release_date' => $format_date,

...