Burst

Burst is a game mechanic which debuted along with the Battle Spirits Heroes anime. It's a type of effect. There are spirits, magic, and now braves that have burst effects. They're cards that are placed face down, keeping secret and activate under certain circumstances (such as when you lose a life).There are many different effects of a burst (such as to summon it without cost). The cards with burst usually can be played as a regular card also.

This effect allows the player to suprise the opponent. Cards with this ability include The HeroDragon Lord-Dragon and Burst Flame.

Also, there is Burst Tribute effect, which is a combination of Burst and Tribute. It's a special effect which only The SuperHero Lord-Dragon-Saviour contains.[1]

The effect follows: [Burst Tribute: After your life is decreased] By moving all the cores on 1 of your spirits in the family "Supreme Hero" to the void, summon this spirit. After that, move as many cores as you like from your field/reserve to your life, until you have up to 5 lives.

For a list of burst, click this.