Its only one card and can target any dragon.
It starts as a speaker, which can cause a dragon to lose a point of attack, any dragon, and gain a point of Max HP. This makes it somewhat dual use. It can weaken the enemy, or [rotect your own.
If you upgrade it, its a Dragon singer, which upgrades both HP and Att, making your dragons more powerful overall.
Its one card, probably other, and can target any dragon.
It is situational, but any dragon only card is. These delay dragons, or change their stats. The upgraded one, the Dragon singer can produce really powerful dragons very quickly.