Gold Corn

When you kill a kobold or werewolf in Errac Tierra Dias or Tierra Noche, there is a 1% chance that you can (quite literally) beat the shit out of them. This Excrement Lump (aka Night Soil in GE-SG) can be used at the farm in Errac (I3/J3) to receive 1 Gold Corn. You can then exchange 10 Gold Corns for a random reward from Vagabond Peddler in New Opoluto (E3). The known rewards are:

1 Amethyst Fragment 1 Veteran G (14m) EXP Card 3 Lv.90 F (150k) EXP Card 1 Sabre Tiger Spinelle 1 Elite Storm Cockatrice Spinelle* 1 Amber Wasp Spinelle* 1 Angler Spinelle* 1 Escudo Preffer Amber 1 Invisible Potion 1 HQ Ruby/Sapphire/Emerald 2 Lv.92 Enchantment Chip 2 Lv.96 Enchantment Chip 1 Lv.100 Enchantment Chip 10 Spearfish 2 Moon Cake 2 Lucky Pouch 3 Handmade Chocolate 3 Heart Choco 1 Mission: Joaquin Defense Barrier

Note (*): These spinelles are sold by the Item Shop in Errac for 2.5m (Elite Storm Cockatrice), 5m (Amber Wasp), and 10m (Angler) vis each. See [v3.0 Feature] Paying Tribute to the Queen.

I have exchanged a fair amount of corns, and these are the rewards I received so far. This post will be updated if I find more possible rewards.