diff --git a/mods/counter-op.lua b/mods/counter-op.lua
new file mode 100644
index 000000000..75d2c1060
--- /dev/null
+++ b/mods/counter-op.lua
@@ -0,0 +1,88 @@
+-- name: Counter-Op
+-- description: All players except the host will try to kill the host
+
+gServerSettings.playerInteractions = PLAYER_INTERACTIONS_PVP
+
+function get_main_character()
+    local np = network_player_from_global_index(0)
+    if np == nil then
+        np = gNetworkPlayers[0]
+    end
+    return gMarioStates[np.localIndex]
+end
+
+function is_main_character(m)
+    local main = get_main_character()
+    return m.playerIndex == main.playerIndex
+end
+
+function does_level_match(m1, m2)
+    local np1 = gNetworkPlayers[m1.playerIndex]
+    local np2 = gNetworkPlayers[m2.playerIndex]
+    if np1.currActNum ~= np2.currActNum then
+        return false
+    end
+    if np1.currAreaIndex ~= np2.currAreaIndex then
+        return false
+    end
+    if np1.currCourseNum ~= np2.currCourseNum then
+        return false
+    end
+    if np1.currLevelNum ~= np2.currLevelNum then
+        return false
+    end
+    return true
+end
+
+function mario_update_local(m)
+    if not is_main_character(m) then
+        local main = get_main_character()
+        local mainNp = gNetworkPlayers[main.playerIndex]
+        --print('>>>', mainNp.globalIndex, mainNp.currAreaSyncValid, mainNp.currLevelSyncValid)
+        --if mainNp.currAreaSyncValid and mainNp.currLevelSyncValid then
+            if not does_level_match(m, main) then
+                warp_to_level(mainNp.currLevelNum, mainNp.currAreaIndex, mainNp.currActNum)
+            end
+        --end
+    end
+end
+
+function mario_update(m)
+    if m.playerIndex == 0 then
+        mario_update_local(m)
+    end
+
+    local np = gNetworkPlayers[m.playerIndex]
+    if is_main_character(m) then
+        m.visibleToEnemies = 1
+        if np.modelIndex == CT_TOAD then
+            np.overrideModelIndex = CT_MARIO
+        end
+    else
+        m.visibleToEnemies = 0
+        if np.modelIndex ~= CT_TOAD then
+            np.overrideModelIndex = CT_TOAD
+        end
+    end
+end
+
+function allow_pvp_attack(m1, m2)
+    return m1.visibleToEnemies ~= m2.visibleToEnemies
+end
+
+function allow_interact(m, obj, interactType)
+    if not is_main_character(m) then
+        if (interactType & INTERACT_WARP) ~= 0 then return true end
+        if (interactType & INTERACT_WARP_DOOR) ~= 0 then return true end
+        if (interactType & INTERACT_STRONG_WIND) ~= 0 then return true end
+        if (interactType & INTERACT_BBH_ENTRANCE) ~= 0 then return true end
+        if (interactType & INTERACT_PLAYER) ~= 0 then return true end
+        return false
+    end
+
+    return true
+end
+
+hook_event(HOOK_ALLOW_INTERACT, allow_interact)
+hook_event(HOOK_ALLOW_PVP_ATTACK, allow_pvp_attack)
+hook_event(HOOK_MARIO_UPDATE, mario_update)
\ No newline at end of file