1E's Fiend Folio
I've been playing D&D since 1981 and the first AD&D book I bought - I otherwise relied on photocopies of the "big three" plus my Basic and Expert sets - was the Fiend Folio in 1982.
To say that the Fiend Folio was a mixed bag was a major understatement. It does not measure up well against the first Monster Manual or Monster Manual 2. (And it really surprised me when I read an interview with Mike Mearls some years ago where he openly admitted to advocating for the inclusion of more Fiend Folio monsters in the early 4E releases. That's why we got crap like the berbalang rather than more of the classic D&D monsters like, for example - frost giants, in the first Monster Manual. It also explains why I don't like what I have read about D&D Next: clearly I've got different design philosophies to Mike Mearls.)
One of the silly monsters that was included was the flail snail. Now this is a monster I completely ignored for nearly 30 years, treating it as just another bad idea from the Fiend Folio. However, along came Paizo with Misfit Monsters Redeemed and this picture:
Suddenly, the flail snail didn't quite seem so irredeemably silly anymore. Anyway, last night I was reading the excellent Mordenkainen's Magnificent Emporium and noticed the entry for armour of scintillating colours and thought back to how the original flail snail's shell had the same effect as a robe of scintillating colours, the inspiration for the 4E item. So, using Paizo's write-up plus the entry in Mordenkainen's Magnificent Emporium as inspiration, I decided to stat up the flail snail.
The biggest concern I have about this monster in play is its low speed. With the right terrain, a ranged attacker should be able to reduce the 'snail to mincemeat quite easily. However, in terrain that enforces close combat, the 'snail should prove to be a real brute as it can knock enemies prone as an at-will attack and then use a move action to basically keep them prone for at least one more turn. Unfortunately, it doesn't have any other ability to take advantage of prone enemies; if I decide to amend the stat block I might just simply give it a damage bonus against them as it is a brute rather than a controller.
Looking at it again, I could also see it being a soldier. After all, the shell suggests a high AC - I went with resist 5 all while unbloodied to represent the shell's effects - and while it doesn't mark its targets, it certainly stops them from getting away.
Yeah, it really is a soldier.
Before I go back into Adventure Tools and finesse it some more, I need to give some thought as to what other monsters I can pair it with. It really needs some artillery or controllers that it can defend but the key is going to be the terrain because its slow movement really does limit it on the battlefield.
Hmmm, maybe that ghaunadan invoker of Ghaunadaur I was thinking about today has managed to train a group of flail snails to follow him by feeding them some sort of corrupt Far Realm-infused slime....