The Don makes Goblin King Jareth an offer he can't refuse. The diamond thus slips into my hands! I hide that diamond in one of those fancy combination safes, hidden behind a painting. Now here's the deal: all the paintings look the same, but only one hides the safe - the rest are traps.....!
I check the paintings with my friend Admiral Akbar. I never trip a single trap as he seems to have a sixth sense about those things. I give the diamond to Dr. Robotnic saying that it is a dormant Chaos Emerald.
I borrow Pinkie Pie's helicopter thingy and get the diamond. I leave it in the lair of the green dragon that still lives in the Everfree Forest.
I slay the dragon with..... errr..... "something" and retrieve the diamond. I place the diamond in a pile of rock candy, and somepony ate the diamond.
Using cartoon physics, I reach in their mouth and pull it out. I place the diamond under the care of Angel the bunny
I give Angel 'The Stare' and she drops it and I take it. I give the diamond to an Ursa Major and tell it ii's his baby Ursa minor.
I get "The Great and Powerful Trixie" to vanquish the dreaded Ursa Major. I give the diamond to Rainbow Dash, and the only way to get it is to beat her in a race. [And even if you beat her, she doesn't have the real diamond.]
Not sure if you're lying....better be safe. I recruit the Wonderbolts to chase down Dash and get the diamond. If it is truly fake, I'll amplify Rarity's gem detection magic with some spell Twilight read in a book. Rarity finds the diamond and I let her put it in her new dress, regardless if she found it or the Wonderbolts found it first. which she wears for hours on end.
I like the way you think Since Rarity found it. [My choice] Anyways, I make Rarity famous in exchange for the diamond on the dress. I give the diamond to Rainbow Dash...again! And the only way to get the diamond is to beat her in a race, but this time, the Wonderbolts are on her side! [And even if you beat her, she doesn't have the real diamond.]
I mug Rainbow Dash. Problem solved. I then take the diamond and put in a paradox box. You can't open the box with out being forced to think about a paradox FOREVER.
Ok. I think about a paradox and open the box. I'll have forgotten about it by tomorrow morning. I mix the diamond in with a pile of similar-looking duds.
I mug you as well. I then give the diamond to Lauren Faust as a gift for the show she made. (Check mate)
I trick Tenortrouble into mugging Lauren Faust. (you were on such a roll you couldn't help yourself.) The diamond is then confiscated by the police.
However, I owned the police in that district, so I have it now. I then toss the diamond into the Pacific coast.
I....scuba dive for it. I throw the diamond into a pit of barbed wire, salt, piranhas, and whatever else is nasty and dangerous.
Since I'm already in the pit, I pick up the diamond and leave. I then magically download the diamond to /b/.