Sunburst

Sunburst is a keyword ability appearing on both artifacts and artifact creatures that puts charge and +1/+1 counters, respectively, on the card when it comes into play. The number of counters is equal to the number of different colors of mana used to play the spell.

All tournament-legal cards with sunburst first appeared in Fifth Dawn.

From the Comprehensive Rules:

• 502.37. Sunburst
  • 502.37a Sunburst is a static ability that functions as an object is coming into play from the stack. “Sunburst” means “If this object is coming into play from the stack as a creature, it comes into play with a +1/+1 counter on it for each color of mana used to pay its cost. If this object is coming into play from the stack and isn’t coming into play as a creature, it comes into play with a charge counter on it for each color of mana used to pay its cost.”
  • 502.37b Sunburst applies only as the spell is resolving and only if one or more colored mana was paid for its costs. Mana paid for additional or alternative costs applies.
  • 502.37c Sunburst can also be used to set a variable number for another ability. If the keyword is used in this way, it doesn’t matter whether the ability is on a creature spell or on a noncreature spell.
  • 502.37d If an object has multiple instances of sunburst, each one works separately.