Jim organizing a gift exchange

You are Jim. It is the day of Christmas Eve and your friends Jason, Tony, Cory and Emily are over to your place to open your presents together.
In the corner of your living room is a fairly sized Christmas tree, decorated to the brim with glitter and ornaments. Underneath the tree are six gifts. Together you stand in front of the tree and see the gifts: a medium-sized gift from Jason to Tony, a large-sized gift from Jim to Cory, a very large-sized gift from Tony to Jim, a very large-sized gift from Cory to Emily, a medium-sized gift from Emily to Jason. The sixth gift has no label at all, so you all stare at each other in confusion. You take the initiative, grab that package and open it up to see inside... A small box.

The contents of this package are not what you expected. There is nothing in here that can be considered "Christmas" or even "a present".
Here are the contents of the package: 
A small wooden toy car. It's wheels look like they're made out of wood, but there is no engine inside.
A set of four plastic keys.
You look inside the box to see a letter made from cut up magazines with instructions on what to do with the plastic keys. The letter reads:
1. Choose a key.
2. Find the correct keyhole.
3. Turn the key and open the lock.
4. ????
5. PROFIT!!!
Everyone each takes a key and splits up looking for keyholes. You search high and low, but can't find a single keyhole anywhere in your house.

> You set the toy car on the ground. It drives out the door, and you follow it.
As the toy car drives out into the road, you follow it. Where it stops and rolls away after going over a crack in the road, you run after it.
You see Warren, a small chest creature with keyholes all over it's body, that sees putting keys into them as a very lewd thing to do. You chase after him.
As the wooden car drives along the road into the forest, you follow it. It's not long before you find yourself lost in a part of the forest you've never been to before.

> You see a large tree with a keyhole in it.
You find yourself in front of a large tree. Markings of an unknown language cover the tree. The car drives over to it and the wheels lock up, preventing the car from driving any further.
You continue to try the plastic keys until one works. You open the door in the tree and see a staircase leading down. You walk down the stairs and find yourself in a hallway that leads to three rooms.
There is keyhole in the third room. You try the three keys on the keyhole. As the last one turns, the door begins to open.
Opening the door reveals a room with a table on the opposite side of the room. And sitting at the table is... your future self!
"hello,"
Standing next to your future self is Vinz Clortho, the Keymaster of Gozer.  His hands and arms are moving at a rapid pace. He is signing rapidly. It is almost as if you can see the air around him vibrating due to the speed that he is signing.
'Hell...ooo' your future self says to you. 'Hell...ooo, I know... you are... confused. You are... seeing yourself. No, don't... freak out.

> You put one of the plastic keys in his mouth and turn it.
The key falls out of his mouth and onto the table.
'Took you... long enough... Keymaster... to arrive.'
Future You holds out one of his arms.

> You notice it is covered in strange writing as you take your hand.
The arm you are holding seems normal... until you notice the writing all over his arm and realize it is your own writing.
'Do you... know what this writing says?' your future self signs slowly.
You read the writing your future self's arm. It says:
Vinz Clortho, Keymaster of Gozer
Malphas, the Gatekeeper of Gozer
Ivo Shander, the Prime Minister of the Underworld
Zuul, the Gatekeeper of the Underverse
Slimer, Herald of the Terror Dogs
The Stay-Puft Marshmallow Man, Destructor of Your Dreams
'Yes.' you sign back.
'Then you... know our enemy... The Terror Dogs... the Gatekeeper... Zuul, and Ivo Shander, the Prime...'
Future You begins to gag on a piece of ham he pulls out of his robe.

> You future you says "we all do this. Would you care for a piece of hairy ham?"
"We all do this?" you ask, puzzled.
'What... Oh! The ham. Yes, we all enjoy delicious... human food. Hmmm... Would you care for some?

> You slam your fists on the table and ask "Where's the fucking profit??"
Futre You, and the real You both look shocked.
'Profits... Ivo Shander... he's razing... entire city blocks... to the ground... tearing down... building... and rebuilding anew...
You use the final key on the piece of hairy ham sitting on the table and suddnely a keytar appears in your hands.
'Holy shit.' you say as the Keymaster of Gozer looks on in horror.
Soon enough, your mind is filled with horrifying knowledge of something called "music".

> You belt out a face melter and turn Gozer to ash.
You place the keytar on your lap as the Keymaster of Gozer stares at you in shock. You belt a face melter that could wake the dead and turn the Keymaster of Gozer into ash.

> You go on a world music tour and profit beyond your wildest dreams.
Sadly, many of your fans and most of the world are driven insane by your music.
The world ends... thanks to you and your stupid face melters.
The moral of the story: do not try to be the new Keymaster of Gozer.