Episode 13 features underwater mines, and I've been thinking I'd like to use them as one of my common artifacts. The name "Underwater Mine" really suggests damage to attackers, but also suggests it really wants a symbol somewhere on the card. I've been through quite a few potential designs before finally concluding this is a good way to do it.
The result is a version of Impeccable Timing with the significant drawback that it's telegraphed in advance, but the upside that if you can rustle up a blue mana from somewhere then it becomes a cantrip.
It also triggers revolt in decks including red or green as well as white, but Land Mine is more directly designed for that use case.
As discussed on Land Mine: this card wants to be accessible to the (Red-green archetype), so remove the colour-specificity. Was 3-to-attacker if spent, draw a card if spent.
Land Mine didn't have any good designs mirroring the Repel Intruders-style design here, so I removed the coloured mana, making this more like Scalding Cauldron.
I considered adding back in some to this card to play up the underwater-ness. But that runs into a weird issue. Imagine the following cards:
A 1/1 Merfolk creature, costing , with ", Sacrifice ~: ~ deals 3 damage to target attacking creature". That's a flagrant colour pie violation, on par with Psionic Blast.
A noncreature artifact, costing , with the same ability. Like Witching Well but zapping an attacker. That's still clearly way out of pie for a blue card.
A noncreature artifact, costing , with the same ability. That's perfectly fine in the colour pie, with plenty of precedent, from Aeolipile to Moonglove Extract to Springjaw Trap.
I was considering making this have a first line of text saying "When ~ ETBs, if was spent to cast it, draw a card." But that I think makes this feel enough like a blue-coloured card that the activated ability feels out of pie.
This isn't an exact science, but I think it's better to leave this as it is. But it's interesting!
, Sacrifice Underwater Mine: It deals 3 damage to target attacking creature.
Episode 13 features underwater mines, and I've been thinking I'd like to use them as one of my common artifacts. The name "Underwater Mine" really suggests damage to attackers, but also suggests it really wants a
symbol somewhere on the card. I've been through quite a few potential designs before finally concluding this is a good way to do it.
The result is a version of Impeccable Timing with the significant drawback that it's telegraphed in advance, but the upside that if you can rustle up a blue mana from somewhere then it becomes a cantrip.
It also triggers revolt in decks including red or green as well as white, but Land Mine is more directly designed for that use case.
As discussed on Land Mine: this card wants to be accessible to the (Red-green archetype), so remove the colour-specificity. Was 3-to-attacker if
spent, draw a card if 
spent.
Land Mine didn't have any good designs mirroring the Repel Intruders-style design here, so I removed the coloured mana, making this more like Scalding Cauldron.
I considered adding back in some
to this card to play up the underwater-ness. But that runs into a weird issue. Imagine the following cards:
I was considering making this have a first line of text saying "When ~ ETBs, if
was spent to cast it, draw a card." But that I think makes this feel enough like a blue-coloured card that the activated ability feels out of pie.
This isn't an exact science, but I think it's better to leave this as it is. But it's interesting!