diff --git a/source/blood/src/actor.cpp b/source/blood/src/actor.cpp
index cf68e2570..1e83a2a4d 100644
--- a/source/blood/src/actor.cpp
+++ b/source/blood/src/actor.cpp
@@ -1707,7 +1707,7 @@ MissileType missileInfo[] = {
     }
 };
 
-THINGINFO thingInfo[] = {
+const THINGINFO thingInfo[] = {
     //TNT Barrel
     {
         25,
@@ -3868,7 +3868,7 @@ void actImpactMissile(spritetype *pMissile, int hitCode)
     sectortype *pSectorHit = NULL; XSECTOR *pXSectorHit = NULL;
 
     actHitcodeToData(hitCode, &gHitInfo, &nSpriteHit, &pSpriteHit, &pXSpriteHit, &nWallHit, &pWallHit, &pXWallHit, &nSectorHit, &pSectorHit, &pXSectorHit);
-    THINGINFO *pThingInfo = NULL; DUDEINFO *pDudeInfo = NULL;
+    const THINGINFO *pThingInfo = NULL; DUDEINFO *pDudeInfo = NULL;
 
     if (hitCode == 3 && pSpriteHit) {
         switch (pSpriteHit->statnum) {
@@ -4211,7 +4211,7 @@ void ProcessTouchObjects(spritetype *pSprite, int nXSprite)
                 if (pSprite2->statnum == kStatThing)
                 {
                     int nType = pSprite2->type-kThingBase;
-                    THINGINFO *pThingInfo = &thingInfo[nType];
+                    const THINGINFO *pThingInfo = &thingInfo[nType];
                     if (pThingInfo->flags&1)
 
                         pSprite2->flags |= 1;
@@ -4546,7 +4546,7 @@ int MoveThing(spritetype *pSprite)
     int nSprite = pSprite->index;
     int v8 = 0;
     dassert(pSprite->type >= kThingBase && pSprite->type < kThingMax);
-    THINGINFO *pThingInfo = &thingInfo[pSprite->type-kThingBase];
+    const THINGINFO *pThingInfo = &thingInfo[pSprite->type-kThingBase];
     int nSector = pSprite->sectnum;
     dassert(nSector >= 0 && nSector < kMaxSectors);
     int top, bottom;
@@ -5829,7 +5829,7 @@ void actProcessSprites(void)
         if (pXSector && pXSector->panVel && (pXSector->panAlways || pXSector->state || pXSector->busy))
         {
             int nType = pSprite->type - kThingBase;
-            THINGINFO *pThingInfo = &thingInfo[nType];
+            const THINGINFO *pThingInfo = &thingInfo[nType];
             if (pThingInfo->flags & 1)
 
                 pSprite->flags |= 1;
@@ -6546,7 +6546,7 @@ spritetype * actSpawnThing(int nSector, int x, int y, int z, int nThingType)
     pSprite->type = nThingType;
     dassert(nXThing > 0 && nXThing < kMaxXSprites);
     XSPRITE *pXThing = &xsprite[nXThing];
-    THINGINFO *pThingInfo = &thingInfo[nType];
+    const THINGINFO *pThingInfo = &thingInfo[nType];
     pXThing->health = pThingInfo->startHealth<<4;
     pSprite->clipdist = pThingInfo->clipdist;
     pSprite->flags = pThingInfo->flags;
diff --git a/source/blood/src/actor.h b/source/blood/src/actor.h
index 42b785ca8..6d7e8de6d 100644
--- a/source/blood/src/actor.h
+++ b/source/blood/src/actor.h
@@ -186,7 +186,7 @@ extern WEAPONITEMDATA gWeaponItemData[];
 extern ITEMDATA gItemData[];
 extern MissileType missileInfo[];
 extern EXPLOSION explodeInfo[];
-extern THINGINFO thingInfo[];
+extern const THINGINFO thingInfo[];
 extern VECTORDATA gVectorData[];
 
 extern int gDudeDrag;
diff --git a/source/blood/src/aiunicult.cpp b/source/blood/src/aiunicult.cpp
index 73e726a2b..c81d69b17 100644
--- a/source/blood/src/aiunicult.cpp
+++ b/source/blood/src/aiunicult.cpp
@@ -284,7 +284,7 @@ static void ThrowThing(int nXIndex, bool impact) {
     if (curWeapon < kThingBase || curWeapon >= kThingMax)
         return;
 
-    THINGINFO* pThinkInfo = &thingInfo[curWeapon - kThingBase];
+    const THINGINFO* pThinkInfo = &thingInfo[curWeapon - kThingBase];
     if (!pThinkInfo->allowThrow) return;
 
     if (!playGenDudeSound(pSprite, kGenDudeSndAttackThrow))