diff --git a/forge-ai/src/main/java/forge/ai/ability/FogAi.java b/forge-ai/src/main/java/forge/ai/ability/FogAi.java
index ee2961a2996..82b768181cf 100644
--- a/forge-ai/src/main/java/forge/ai/ability/FogAi.java
+++ b/forge-ai/src/main/java/forge/ai/ability/FogAi.java
@@ -5,9 +5,12 @@ import forge.ai.ComputerUtil;
 import forge.ai.ComputerUtilCombat;
 import forge.ai.SpellAbilityAi;
 import forge.game.Game;
+import forge.game.card.Card;
+import forge.game.card.CardPredicates;
 import forge.game.phase.PhaseType;
 import forge.game.player.Player;
 import forge.game.spellability.SpellAbility;
+import forge.util.Aggregates;
 
 public class FogAi extends SpellAbilityAi {
 
@@ -35,6 +38,25 @@ public class FogAi extends SpellAbilityAi {
             return false;
         }
 
+        if ("SeriousDamage".equals(sa.getParam("AILogic")) && game.getCombat() != null) {
+            int dmg = 0;
+            for (Card atk : game.getCombat().getAttackersOf(ai)) {
+                if (game.getCombat().isUnblocked(atk)) {
+                    dmg += atk.getNetCombatDamage();
+                } else if (atk.hasKeyword("Trample")) {
+                    dmg += atk.getNetCombatDamage() - Aggregates.sum(game.getCombat().getBlockers(atk), CardPredicates.Accessors.fnGetNetToughness);
+                }
+            }
+
+            if (dmg > ai.getLife() / 4) {
+                return true;
+            } else if (dmg >= 5) {
+                return true;
+            } else if (ai.getLife() < ai.getStartingLife() / 3) {
+                return true;
+            }
+        }
+
         // Cast it if life is in danger
         return ComputerUtilCombat.lifeInDanger(ai, game.getCombat());
     }
diff --git a/forge-gui/res/cardsfolder/s/spike_weaver.txt b/forge-gui/res/cardsfolder/s/spike_weaver.txt
index 2c38cc864e1..5937873b693 100644
--- a/forge-gui/res/cardsfolder/s/spike_weaver.txt
+++ b/forge-gui/res/cardsfolder/s/spike_weaver.txt
@@ -4,6 +4,6 @@ Types:Creature Spike
 PT:0/0
 K:etbCounter:P1P1:3
 A:AB$ PutCounter | Cost$ 2 SubCounter<1/P1P1> | ValidTgts$ Creature | CounterType$ P1P1 | CounterNum$ 1 | SpellDescription$ Put a +1/+1 counter on target creature.
-A:AB$ Fog | Cost$ 1 SubCounter<1/P1P1> | SpellDescription$ Prevent all combat damage that would be dealt this turn.
+A:AB$ Fog | Cost$ 1 SubCounter<1/P1P1> | AILogic$ SeriousDamage | SpellDescription$ Prevent all combat damage that would be dealt this turn.
 SVar:Picture:http://www.wizards.com/global/images/magic/general/spike_weaver.jpg
 Oracle:Spike Weaver enters the battlefield with three +1/+1 counters on it.\n{2}, Remove a +1/+1 counter from Spike Weaver: Put a +1/+1 counter on target creature.\n{1}, Remove a +1/+1 counter from Spike Weaver: Prevent all combat damage that would be dealt this turn.