add etbLoseLife keyword as (K:etbLoseLife:3); The AI is built into Spell_Permanent so Compy won't do anything stupid.

-convert Serpent Warrior as an example.

res/cardsfolder/serpent_warrior.txt

@@ -3,6 +3,7 @@ ManaCost:2 B
 Types:Creature Snake Warrior
 Text:When CARDNAME enters the battlefield, you lose 3 life.
 PT:3/3
+K:etbLoseLife:3
 SVar:Rarity:Common
 SVar:Picture:http://resources.wizards.com/magic/cards/9ed/en-us/card83364.jpg
 SetInfo:8ED|Common|http://magiccards.info/scans/en/8e/161.jpg

src/forge/Card.java

@@ -1112,6 +1112,13 @@ public class Card extends MyObservable {
         manaAbility.clear();
     }
     
+    public Spell_Permanent getSpellPermanent() {
+    	for(SpellAbility sa:spellAbility) {
+    		if(sa instanceof Spell_Permanent) return (Spell_Permanent)sa;
+    	}
+    	return null;
+    }
+    
     public void clearSpellKeepManaAbility() {
         spellAbility.clear();
     }

src/forge/CardFactory.java

@@ -2938,6 +2938,42 @@ public class CardFactory implements NewConstants {
         	card.addComesIntoPlayCommand(etbGainLife);
         } // etbGainLife
         
+        // Generic enters the battlefield lose life
+        // there is also code in Spell_Permanent canPlayAI to handle that part
+        if (hasKeyword(card, "etbLoseLife") != -1) {
+        	int n = hasKeyword(card, "etbLoseLife");
+
+        	String parse = card.getKeyword().get(n).toString();
+        	card.removeIntrinsicKeyword(parse);
+        	
+        	String k[] = parse.split(":");
+
+        	final int num = Integer.parseInt(k[1]);
+        	card.getSpellPermanent().setLoseLifeAmount(num);
+
+        	// performs the gain
+        	final SpellAbility etbLoseLifeAbility = new Ability(card, "0") {
+        		@Override
+        		public void resolve() {
+        			card.getController().loseLife(num, card);
+        		}
+        	};
+
+        	// when the card enters the battlefield
+        	Command etbLoseLife = new Command() {
+				private static final long serialVersionUID = -6797619430597211329L;
+
+				public void execute() {
+        			StringBuilder sb = new StringBuilder();
+        			sb.append(card.getController()).append(" loses "+num+" life");
+        			etbLoseLifeAbility.setStackDescription(sb.toString());
+
+        			AllZone.Stack.add(etbLoseLifeAbility);
+        		}
+        	};
+        	card.addComesIntoPlayCommand(etbLoseLife);
+        } // etbLoseLife
+        
 
         // Generic destroy all card
         /* Cards converted to AF_DestroyAll

src/forge/CardFactory_Creatures.java

@@ -1551,7 +1551,7 @@ public class CardFactory_Creatures {
             card.addComesIntoPlayCommand(intoPlay);
         }//*************** END ************ END **************************
         
-
+        /*
         //*************** START *********** START **************************
         else if(cardName.equals("Serpent Warrior")) {
             SpellAbility summoningSpell = new Spell_Permanent(card) {
@@ -1586,7 +1586,7 @@ public class CardFactory_Creatures {
             };
             card.addComesIntoPlayCommand(intoPlay);
         }//*************** END ************ END **************************
-        
+        */
         
         //*************** START *********** START **************************
         else if(cardName.equals("Eviscerator")) {

src/forge/Spell_Permanent.java

@@ -7,6 +7,11 @@ public class Spell_Permanent extends Spell {
     
     private boolean willChampion = false;
     private String championType = null;
+    private int loseLifeAmount;
+    
+    public void setLoseLifeAmount(int a) {
+    	loseLifeAmount = a;
+    }
     
     /////////////////////
     ///////
@@ -187,6 +192,10 @@ public class Spell_Permanent extends Spell {
             	return false;
         }
 
+        if(!(AllZone.ComputerPlayer.getLife() > (loseLifeAmount+3))) {
+    		return false;
+    	}
+        
         return super.canPlayAI();
     }//canPlayAI()