There is a Kickstarter for 'overkill' and 'underkill' dice and they sound like they'd be fun to use as a DM but at the same time since I am still fairly new to d&d I don't know how I could use them or when/if they'd come up in a fairly relaxed game.

Basically the overkill dice is a d20 but 19 of the sides have a 20 and 1 side has a Nat 1 and the 'underkill' dice is the same but 19 1s and 1 20.

I feel like the underkill dice could be fun to roll to decide a players fate after rolling a Nat 1 in roleplay scenarios but that's all I can't think of at the moment.

Any ideas?

"You see how the red dragon flys past the tower where you are standing. His breath engulfes the town beneath you in fire. Villagers scream in agony and fear. What do you do?"

Fighter: "I take a deep breath, run towards the open and jump right as the dragon flies by, aiming my two handed sword to stab him right in the back of his neck"

... roll underkill. Nat 20? Dragon's dead. Anything else? The fighter misses and falls to his death.

So, basically I would use the underkill dice for all scenes that are high-risk, high-reward.

Or when someone really wants to snipe someone. Called shots.

I will say that the overkill die would be useful to wild magic sorcerers. They are supposed to roll a d20 after casting a spell that is level 1 or higher. If they roll a 1, they have to then roll off the wild magic surge table. So rolling a 2 would be absolutely no different from rolling a 20, so they might as well all be 20s.

Not sure what the underkill die would be good for in that respect, however, unless the player just really wanted to roll off the wild magic surge table.

If you want a d20 roll to have a 95% chance of a crit fail and a 5% chance of a crit success, just say so. "Anything but a 20 on this roll counts as a natural 1." The numbers can mean anything you want. That's D&D. You don't have to waste money on novelty dice that are useless outside of very niche rolls.

Regardless, this doesn't even sound fun as a player. If I ask my DM if I can do something and he just flat-out tells me "You only have a 5% chance of this succeeding, otherwise, you **** it up as badly as possible" then I'm not gonna make that roll.  Making it a surprise would be even worse. Someone's gonna get pissed when they have a +17 to an ability but you tell them they have to roll this die that effectively invalidates their character.

Quote from AetherStorm >>

If you want a d20 roll to have a 95% chance of a crit fail and a 5% chance of a crit success, just say so. "Anything but a 20 on this roll counts as a natural 1." The numbers can mean anything you want. That's D&D. You don't have to waste money on novelty dice that are useless outside of very niche rolls.

Regardless, this doesn't even sound fun as a player. If I ask my DM if I can do something and he just flat-out tells me "You only have a 5% chance of this succeeding, otherwise, you **** it up as badly as possible" then I'm not gonna make that roll.  Making it a surprise would be even worse. Someone's gonna get pissed when they have a +17 to an ability but you tell them they have to roll this die that effectively invalidates their character.

^^^ This.

I see no point to these dice but to each their own.