I could use some rules templating help on both of these abilities. Thanks.

Seem fine to me, albeit really unusual. I think dealing 0 damage to this might kill it; which is an odd side effect. But maybe not problematically odd.

Cool. I remember seeing things like Erode discussed in a few places. It was being proposed over on the Wizards forum as a potential evergreen keyword for blue. There's not very many cards on Multiverse that I can find with it, which surprises me somewhat given how often I've seen it in other parts of the custom card internet, but Psychic Tim does something similar.

We discussed the second ability a bit over on Thoughtwisp and Shimmering Glory. My reminder text for the second ability was "(Any positive amount of damage destroys it.)" Thankfully the rules say that 0 damage is no damage at all, but obviously 1 damage will kill anything like this (assuming the natural rules tweak to 704.5g).

Alright. I guess the second ability checks out. But how about reminder text like this. (A source cannot deal 0 or less damage.) or (0 damage is not damage.) or (Any amount of damage greater than 0 still destroys creatures with 0 toughness normally.)

But I'm still not sure I've worded Erode correctly. I was trying to template it after Infect, but that may have been a little too cute. I feel like it needs to say something about the amount of cards put into that player's graveyard.

Maybe something like, "This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of putting a number of cards from the top of that player’s library equal to this creature's power into his or her graveyard." But that's really wordy... Any suggestions?

Reminder text doesn't have to be precisely the rules text; if it was, we wouldn't have the comprules, and cards would all be be the size of desks.

Infect doesn't spell out exactly what "damage in the form of" is either, I think it's fine. "Works like infect" is pretty obviously one-card-per-damage.

It's kinda an interesting ability - very powerful against creatures; very weak against players. Sadly, means "This creature is a blocker" - so be worried about ground stalls.

Templating based on infect is precisely the way to do it. So your wording, "deals damage to players in the form of putting cards from the top of that player's library into his or her graveyard", is completely fine. You could perhaps say "putting that many cards from the top etc", if you wanted, but I think it's fine without "that many".

I think it's much clearer to say "(Any positive amount of damage destroys it)" than to try to mention 0 explicitly in the reminder text.

Dying is a conditional check, not an action. While the grammar in English sounds fine, however, to die is not an official rules action (yet). So, "don't die" should be replaced with "aren't put into the graveyard".

The comp rules say >700.4. The term dies means "is put into a graveyard from the battlefield."

If this was to be an official ability, I'm sure the comp rules would have >700.4a. The phrase "don't/doesn't die" means "aren't/isn't put into a graveyard from the battlefield," respectively.

would be appended. Since this is a fan set, you can assume the comp rules are adjusted however you need. Basically, if it sounds "right," use it.

sure we can assume whatever we want. nevertheless, such rules must need be clarified to the full extent of being viable and clear. that is why, for instance, WotC officially discontinued unblockable and indestructible even if they are easily understood by the laymen. However, such terms have no official rules authority. Unblockable has been replaced by a more official text (can't be blocked), and indestructible became a keyword with explicit rules.

Die in this case has the same issues like bury back in the day. Bury has been discontinued for 20 years and they never looked back.

I think I've come up with some good reminder text for both Erode and the second ability. What do you guys think?

I mean, a creature having 0 toughness is interesting, but what exactly is it accomplishing on this card? Seems to me with that reminder text that it's functionally almost exactly the same. And even if it died by being dealt 0 damage...how often does that really come up? Walls, Fireball for 0? Just seems like it's being cool for coolness's sake, not for any real functionality.

As for Erode, it's strange how much better the ability is against creatures than against players.

I love the name Mind Crabs. And I love the idea of Mind Crabs having a higher power than toughness. I am now going to make 12-17 cards all named Mind Crabs. GOOD DAY SIR!

Didn't this use to say "Creatures you control don't die for having 0 or less toughness"? That was a much more interesting (and relevant) ability.

Here's what this card actually turned out to be. http://lordmarlin.tumblr.com/post/57365377646/for-more-awesome-tcg-stuff-check-out-my-blog