This one is simply based on what I consider to be the coolest beetle I often see. Envisaged as a low Expert level threat, something that a party adventuring in the wilderness for the first time will be terrified of.
Devils Coach Horse
by Cab Davidson
STATS (BECMI) Devils Coach Horse Armor Class 2 Hit Dice 4+1 Move 180' (60') Attacks 1 bite + special Damage 2d6+special No. Appearing 1d2 (1d2) Save As F2 Morale 9 Treasure Type V + special Intelligence 0 Alignment Neutral XP Value 375 The dangerous devils coach horse is a giant black beetle, up to 8’ long, with an extended central body section (thorax) and massive jaws in front of its mouthparts. It is extremely rapid, and can charge into combat for double damage on the first round. Any successful hit thereafter necessitates its victim make a save vs. paralysis or be caught in its great jaws, where they will take 2d6 damage until either they or the devils coach horse is killed.
If seriously threatened the devils coach horse can release a putrid, buning oil from its abdomen. Any creatures other than devils coach horse beetles must make a save vs. poison or be incapacitated by the burning sensation this creates, unable to pursue (but able to defend themselves normally) for 1d6 rounds, typically allowing the beetle to escape.