As an example, I went to Gatherer and randomly generated Stone Rain. That's almost reasonable. So I created Pumice Fields to help negate the impact of land destruction.

If something weak comes up, like Gorilla Warrior, pretend its a legitimate badass, and we need to get rid of it, and not the cards surrounding it (I know if Gorilla Warrior was a monster, then it probably infers something else has gone very wrong, and the problem isn't the Gorilla... but just play along for the sake of this challenge.) Here's hoping someone picks up a Razor Boomerang.

I, uh, kinda went the other direction. I drew Mox Jet and came up with Artifact Lash.

So re-rolled Rod of Ruin to come up with Fangren Stalker

I like this challenge.

Heh. This is indeed fun. Trying to pretend random gubbins are the tournament powerhouses.

I got Gaea's Skyfolk, for which I created Hopesucker. Then I got Artisan's Sorrow, for which I created Culture Preserver. (In between I got Mountain, which I decided to ignore rather than take as "print a harsh Mountain-hoser like Conversion".)

Well, let's try rolling random within multiverse... Mind Flip nets me Mind Trap

I made Vampire Septmage as an answer to Pentavus :)

For ref, in a recent podcast Maro called out, um , Kor Firewalker I think, as just such an answer card - in that case, red needed hosing down hard.

­Form of the Kraken vs Seasinger

­Nightfall Predator -> Arena Vulture though I fear it's also a combo with, not just a flat squasher of)

­Acolyte of the Void answering Knollspine Invocation and Swarmstone answering Mindlash Sliver.

Created Leyline Tripweb to deal with an out of control Piracy in Standard.

Rolled Skyclaw Thrash and created Gambling Restrictions + Rolled Righteous Cause and created Shattered-Skull Orator

I rolled Ghitu Encampment and answered it with Tamiyo's Observer.
I then rolled Life from the Loam and answered it with Eldrazi's Wake.
Then I rolled Gargoyle Castle and answered it with Voidslime's Etchings.

Rolled Jace's Ingenuity, and created Wardens of the Wood to keep the card in check.

Rolled Gruul Charm, so I made Control Gravity.

I rolled Rubinia Soulsinger and created Court of Awakening as an answer.
Then I rolled Swamp Mosquito and though about just submitting Melira, Sylvok Outcast before making Glistening Scepter.

­Cloudseeder is wrecking face so I created Darttongue Toad.

For the problems of Bile Blight I created The Many Faces of Sakashima.