Ivory Charm

This card is an example of effect giving -2/-0 to several cards.

Let's start by looking at this card code :

<?xml version="1.0"?>
<card xmlns="http://sourceforge.net/projects/firemox" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://sourceforge.net/projects/firemox ../../validator.xsd"
 name="Ivory Charm">
<rules-author-comment></rules-author-comment>
 <init>
  <registers>
   <register index="white" value="1"/>
  </registers>
  <colors>white</colors>
  <idcards>instant </idcards>
 </init>
 <abilities>
  <activated-ability playable="this" name="" zone="hand">
   <cost>
    <pay-mana value="manacost"/>
    <action ref="target-dealtable"/>
   </cost>
   <effects>
    <action ref="prevent-1"/>
    <action ref="finish-spell"/>
   </effects>
  </activated-ability>
  <activated-ability playable="this" name="" zone="hand">
   <cost>
    <pay-mana value="manacost"/>
   </cost>
   <effects>
    <action ref="all-creatures"/>
    <action ref="add-2-0-until-eot"/>
    <action ref="finish-spell"/>
   </effects>
  </activated-ability>
  <activated-ability playable="this" name="" zone="hand">
   <cost>
    <pay-mana value="manacost"/>
    <action ref="target-creature"/>
   </cost>
   <effects>
    <tap/>
    <action ref="finish-spell"/>
   </effects>
  </activated-ability>
 </abilities>
</card>