I don't want any spoilers, but I do want a clarification.
I am about to go into mount ordeals. I do not have the rainbow pudding, and I am assuming I want this before I go to Agart. Is there anyway of getting back to antlion's den before going to Agart? I honestly rather not start my game over. Is there an airship in the game, and if so, do I get it before Agart?
Better answer: there is a better place to get Rainbow Pudding to drop at endgame dungeon, so unless you're just in a rush to get the Namingway sidequest done, you might as well wait for that point, when your chances of getting it are as much as 5x higher than with Yellow Jellies.
Also, I believe Basilisk is also in the Antlion's Den, so when you CAN go back there, you can get it no sweat. --- ''Sage'' of The Denpa Men board (Completionist Medal of Honor: http://i48.tinypic.com/20gmued.jpg) 3DS FC: 1590-4884-9269 | Etrian Odyssey 4: DEFINITELY F.O.E.
I... might think it's a good idea to try to get Rainbow Pudding before you attempt to fill out your maps to get Treasure Hunter (which would make getting Rainbow Pudding easier to get, go figure) - if only because you can lay claim to Eye Gouge and Safe Travel once you progress with the Namingway sidequest; both augments can be tremendously helpful in getting through the last area of the final dungeon so you can fill out the map and get TH.
But yeah... it's probably quicker just to move on for now and not worry about it.
. --- "Thou art such a pain in that... confound it all! Now I'm starting to talk like you!" - Sabin "Wow... Me fail English? That's unpossible!"