Advanced format ruling
Eccentric Boy
Card effect (current official text)When using this card as a Synchro Material Monster, the other Synchro Material Monster is 1 monster in your hand. The Synchro Monster that used this card as a Synchro Material Monster cannot activate its effect, its effect(s) is negated, and it is removed from play when removed from the field.
Current rulings for this card are maintained by Konami.
Rulings data courtesy of Format Library — formatlibrary.com. Spotted an inaccuracy? Flag it in the Advanced forum — sourced change requests get reviewed.