Card evolutions
Retrained is the term used to describe when a monster is reprinted with an new or improved effect. examples include "Battle Ox" to "Enraged Battle Ox" and "Magician of Black Chaos" to "Dark Magician of Chaos".
The term "retrained" comes from "Retrained Elf Swordsman," a translation of the Japanese name for "Obnoxious Celtic Guard", who is a retrained version of "Elf Swordsman" ("Celtic Guardian").
Other cards that fit into this catagory are listed below:
