Treno Monster

By going to the weapon shop in Treno, you get the chance to prove your fighting skills by defeating the monster caged underneath. No Exp or AP are in this, but you will get the following rewards from the shopkeep:

Griffin (Disc 2) --> Tonberry Card
Catoblepas (Disc 3) --> 15000 Gil
Amdusias (Disc 3) --> Running Shoes
Behemoth (Disc 4) --> Circlet