REDU format ruling
Cocoon of Evolution

Nearest-era rulings (Tengu, Sept 2011) — no REDU-specific archive exists.
Card effect (current official text)You can target 1 "Petit Moth" you control; equip this card from your hand to that target. While equipped by this effect, the original ATK/DEF of that "Petit Moth" becomes the ATK/DEF of "Cocoon of Evolution".
Rulings
source: Rulings_Tengu (Format Library) — nearest era to REDU (Sept 2011 vs Sept 2012); verify against period sources · 1 era-inappropriate line(s) removedRulings data courtesy of Format Library — formatlibrary.com. Spotted an inaccuracy? Flag it in the REDU forum — sourced change requests get reviewed.