702.30. Kicker

• 702.30a Kicker is a static ability that functions while the spell with kicker is on the stack. "Kicker [cost]" means "You may pay an additional [cost] as you cast this spell." Paying a spell's kicker cost(s) follows the rules for paying additional costs in rules 601.2b and 601.2e-g.
• 702.30b The phrase "Kicker [cost 1] and/or [cost 2]" means the same thing as "Kicker [cost 1], kicker [cost 2]."
• 702.30c Multikicker is a variant of the kicker ability. "Multikicker [cost]" means "You may pay an additional [cost] any number of times as you cast this spell." A multikicker cost is a kicker cost.
• 702.30d If a spell's controller declares the intention to pay any of that spell's kicker costs, that spell has been "kicked." If a spell has two kicker costs or has multikicker, it may be kicked multiple times. See rule 601.2b.
• 702.30e Objects with kicker or multikicker have additional abilities that specify what happens if they are kicked. These abilities are linked to the kicker or multikicker abilities printed on that object: they can refer only to those specific kicker or multikicker abilities. See rule 607, "Linked Abilities."
• 702.30f Objects with more than one kicker cost have abilities that each correspond to a specific kicker cost. They contain the phrases "if it was kicked with its [A] kicker" and "if it was kicked with its [B] kicker," where A and B are the first and second kicker costs listed on the card, respectively. Each of those abilities is linked to the appropriate kicker ability.
• 702.30g If part of a spell's ability has its effect only if that spell was kicked, and that part of the ability includes any targets, the spell's controller chooses those targets only if that spell was kicked. Otherwise, the spell is cast as if it did not have those targets. See rule 601.2c.

Translation:

• 702.30a Kicker is an always on ability allowing players to pay an additional cost when they cast a spell, if they pay that cost then they get to do something additional or different.
• 702.30b Due to previous versions of Kicker there are two ways it may be written, they mean the same thing.
• 702.30c Multikicker is a variant of Kicker where players may pay the cost multiple times rather than only once.
• 702.30d The "kicked" attribute of a spell is determined by the player's intent to pay its cost. A spell may only be kicked once, but may be multikicked multiple times.
• 702.30e No trickery may be used to pay a kicker cost and use a different ability than the one prescribed to the cost.
• 702.30f Again, payment is only good for a specific kicker ability, as outlined on the spell.
• 702.30g If a kicked ability requires decisions to be made, their made at this time, not at any later point.