Goat format ruling
The Dragon's Bead

Card effect (current official text)Discard 1 card from your hand. Negate the effect of a Trap Card that targets 1 face-up Dragon-Type monster and destroy the Trap Card.
Rulings
- When you first activate this card (flip it face-up) you do not have to activate its effect. You cannot flip this card and activate its effect in the same chain. (See Chains, Activation, and Resolution in the Advanced FAQ.)
- If The Dragon’s Bead is already face-up on the field, you may activate it multiple times in the same chain, but you must discard 1 card from you hand as a cost for each activation.
- You cannot activate the effect of The Dragon’s Bead during the Damage Step.
- You cannot activate the effect of The Dragon’s Bead to negate a Trap Card that has already resolved, such as a Nightmare Wheel the opponent activated on a previous turn.
- You can only activate the effect of this card to negate a Trap Card that targets a face-up Dragon monster, so it cannot negate Mirror Force, Waboku, Torrential Tribute, Bottomless Trap Hole, etc."The Dragon’s Bead" must already be applying to negate a Trap targeting a Dragon.
Rulings data courtesy of Format Library — formatlibrary.com. Spotted an inaccuracy? Flag it in the Goat forum — sourced change requests get reviewed.