The combo is Marionette Master in play, with 6 other artifacts and colossus in the graveyard. You win the moment the marionette master resolves.

Step 1. Build board state with prism, puzzleknot, foundry inspector and cultivator caravan.Step 2a. Drop a colossus for free (or free-ish). Use key to the city to make him unblockable and swing for the win twice.Or Step 2b. Drop a colossus, use morbid curiosity to draw 11 cards and find your combo. Drop another colossus for free if you want.Or Step 2c. Use key to put a colossus in the graveyard. Drop a marionette master. Win.

You can tutor for a colossus with either Sanctum of Ugin OR Inventor's Fair.

Don't be afraid to morbid curiosity your skysovergn for gas.