diff --git a/include/monsters.h b/include/monsters.h
index 408f4a888..0573e882d 100644
--- a/include/monsters.h
+++ b/include/monsters.h
@@ -1573,7 +1573,7 @@
         LVL(8, 36, 2, 30, 0), (G_NOCORPSE | 1),
         A(ATTK(AT_ENGL, AD_PHYS, 1, 10),
           NO_ATTK, NO_ATTK, NO_ATTK, NO_ATTK, NO_ATTK),
-        SIZ(0, 0, MS_SILENT, MZ_HUGE), MR_POISON | MR_STONE, 0,
+        SIZ(WT_ETHEREAL, 0, MS_SILENT, MZ_HUGE), MR_POISON | MR_STONE, 0,
         M1_NOEYES | M1_NOLIMBS | M1_NOHEAD | M1_MINDLESS | M1_BREATHLESS
             | M1_UNSOLID | M1_FLY,
         M2_STRONG | M2_NEUTER, 0,
@@ -1582,7 +1582,7 @@
         LVL(8, 12, 2, 30, 0), (G_NOCORPSE | 1),
         A(ATTK(AT_CLAW, AD_FIRE, 3, 6), ATTK(AT_NONE, AD_FIRE, 0, 4),
           NO_ATTK, NO_ATTK, NO_ATTK, NO_ATTK),
-        SIZ(0, 0, MS_SILENT, MZ_HUGE), MR_FIRE | MR_POISON | MR_STONE, 0,
+        SIZ(WT_ETHEREAL, 0, MS_SILENT, MZ_HUGE), MR_FIRE | MR_POISON | MR_STONE, 0,
         M1_NOEYES | M1_NOLIMBS | M1_NOHEAD | M1_MINDLESS | M1_BREATHLESS
             | M1_UNSOLID | M1_FLY | M1_NOTAKE,
         M2_STRONG | M2_NEUTER, M3_INFRAVISIBLE,
@@ -2335,7 +2335,7 @@
         LVL(6, 12, 4, 15, -6), (G_GENO | 2),
         A(ATTK(AT_TUCH, AD_DRLI, 1, 6),
           NO_ATTK, NO_ATTK, NO_ATTK, NO_ATTK, NO_ATTK),
-        SIZ(0, 0, MS_SILENT, MZ_HUMAN),
+        SIZ(WT_ETHEREAL, 0, MS_SILENT, MZ_HUMAN),
         MR_COLD | MR_SLEEP | MR_POISON | MR_STONE, 0,
         M1_BREATHLESS | M1_FLY | M1_HUMANOID | M1_UNSOLID,
         M2_UNDEAD | M2_STALK | M2_HOSTILE, 0,