Posted by : David Guyll March 20, 2013
I always thought it was weird that gelatinous cubes were uniform in size. I would start them out at Medium, or even Small, and scale them up as needed. Also, while it is probably refreshing for adventurers everywhere that they no longer paralyze on contact, it would make a very devious optional trait to tack on from time to time.
I am pretty happy with how these guys are presented mechanically. Unlike 3rd Edition, they do not automatically destroy metal weapons, instead penalizing your damage rolls until the penalty reaches a certain point, after which it is destroyed (which I think should be ported over to the rust monster). They also only have cold and fire resistance as opposed to outright immunity, making them more dangerous than usual to both warriors and wizards alike.
I would consider having them penalize armor, as well, considering it destroyed when the armor bonus is reduced to zero.
I also liked the bit of Ecology in 2nd Edition, where it mentioned some smiths using very small oozes to etch their works. Could make a nasty surprise for characters poking around in an underground forge, especially if they can mimic the color and texture of the surrounding terrain. Speaking of mimicking things...
I both like and dislike limiting the mimic to copying nearby objects. I think it is a fine restriction for "young" mimics until they learn to refine this ability to change shape or, to keep things simple, increase the DC to detect the mimic if it copies an object that it can see. You could also combine the two, and just make younger mimics easier to pick out of the lineup.
For some reason, which might be 4th Edition's object mimic and/or an article I read on scorpions, I also envision them crushing prey, dissolving them with acid, and then slurping it up. At any rate, you could give them an optional trait that lets them vomit acid on enemies, or deal bonus acid damage to creatures that are stuck to them.
This is an example of where I drastrically prefer the 4th Edition version over the previous iterations: it dealt acid damage, ongoing acid damage, and split when it got reduced to half its hit points.
I do not get why it is unaffected by lighting or slashing damage. Is the assumption that each slashing attack cuts it in half? If just breaking its membrane of whatever does the trick, then piercing attacks should also suffice. I would just make it split when it is reduced to half its maximum hit points.
These are actually pretty cool: they can grab you, throw you around, and use you as a shield. The limited telepathy also syncs with their aberration type. The only immediate additions I can think of are the otyugh variants (neo and charnel), and a disease-transmitting bite (like they had in 4th Edition), perhaps as an optional power.
Also pretty solid, though I think that a more elegant solution to its weakening tendrils would be to just impose disadvantage on Strength checks. This would also allow you to give grappled characters an opposed Strength check to resist being reeled in.