- Made Mizzium Meddler use AI SpellMagnet and thus made it AI-playable.

forge-ai/src/main/java/forge/ai/ability/ChangeTargetsAi.java

@@ -28,12 +28,40 @@ public class ChangeTargetsAi extends SpellAbilityAi {
 
         if (sa.hasParam("AILogic")) {
             if ("SpellMagnet".equals(sa.getParam("AILogic"))) {
-                // Cards like Spellskite that retarget spells to itself
+                return doSpellMagnet(sa, topSa, aiPlayer);
+            }
+        }
 
+        // The AI can't otherwise play this ability, but should at least not miss mandatory activations (e.g. triggers).
+        return sa.isMandatory();
+    }
+
+    @Override
+    protected boolean doTriggerAINoCost(Player aiPlayer, SpellAbility sa, boolean mandatory) {
+        final Game game = sa.getHostCard().getGame();
+        final SpellAbility topSa = game.getStack().isEmpty() ? null : ComputerUtilAbility.getTopSpellAbilityOnStack(game, sa);
+
+        if (sa.hasParam("AILogic")) {
+            if ("SpellMagnet".equals(sa.getParam("AILogic"))) {
+                return doSpellMagnet(sa, topSa, aiPlayer);
+            }
+        }
+
+        return true;
+    }
+
+    private boolean doSpellMagnet(SpellAbility sa, SpellAbility topSa, Player aiPlayer) {
+        // For cards like Spellskite that retarget spells to itself
         if (topSa == null) {
             // nothing on stack, so nothing to target
             return false;
         }
+
+        if (sa.getTargets().getNumTargeted() != 0) {
+            // something was already chosen before (e.g. in response to a trigger - Mizzium Meddler), so just proceed
+            return true;
+        }
+
         if (!topSa.usesTargeting() || topSa.getTargets().getTargetCards().contains(sa.getHostCard())) {
             // if this does not target at all or already targets host, no need to redirect it again
             return false;
@@ -43,7 +71,7 @@ public class ChangeTargetsAi extends SpellAbilityAi {
             return false;
         }
         if (!topSa.canTarget(sa.getHostCard())) {
-                    // don't try targeting it if we can't legally target Spellskite with it in the first place
+            // don't try targeting it if we can't legally target the host card with it in the first place
             return false;
         }
 
@@ -61,13 +89,3 @@ public class ChangeTargetsAi extends SpellAbilityAi {
         return true;
     }
 }
-
-        // The AI can't otherwise play this ability, but should at least not miss mandatory activations (e.g. triggers).
-        return sa.isMandatory();
-    }
-
-    @Override
-    protected boolean doTriggerAINoCost(Player aiPlayer, SpellAbility sa, boolean mandatory) {
-        return true;
-    }
-}

forge-gui/res/cardsfolder/m/mizzium_meddler.txt

@@ -4,7 +4,6 @@ Types:Creature Vedalken Wizard
 PT:1/4
 K:Flash
 T:Mode$ ChangesZone | Origin$ Any | Destination$ Battlefield | ValidCard$ Card.Self | Execute$ TrigChange | OptionalDecider$ You | TriggerDescription$ When CARDNAME enters the battlefield, you may change a target of target spell or ability to CARDNAME.
-SVar:TrigChange:AB$ ChangeTargets | Cost$ 0 | TargetType$ Spell,Activated,Triggered | ValidTgts$ Card | DefinedMagnet$ Self | ChangeSingleTarget$ True
+SVar:TrigChange:AB$ ChangeTargets | Cost$ 0 | TargetType$ Spell,Activated,Triggered | ValidTgts$ Card | DefinedMagnet$ Self | ChangeSingleTarget$ True | AILogic$ SpellMagnet
-SVar:RemAIDeck:True
 SVar:Picture:http://www.wizards.com/global/images/magic/general/mizzium_meddler.jpg
 Oracle:Flash (You may cast this spell any time you could cast an instant.)\nWhen Mizzium Meddler enters the battlefield, you may change a target of target spell or ability to Mizzium Meddler.