"D" is for "Drearwig"

Drearwig

No. Enc.:  1d6 (2d4)
Alignment:  Neutral
Movement:  150' (50') 
Armor Class:  4
Hit Dice:  3+1
Attacks:  1 (bite)
Damage:  1d6
Save:  L4
Morale:  9
Hoard Class:  VI
XP:  170

Drearwigs are 3' long, flightless insects that disrupt natural weather patterns with their mere presence.  A lone drearwig can only create vision-obscuring mists and fogs (causing all within the area of effect to suffer a -2 To Hit with all combat rolls), but multiple creatures can generate violent storms, winds, and even blizzards.

Due to their rapacious appetites and turbulent abilities, drearwigs are the bane of farming communities; however, some technical-minded villages utilize the creatures to drive mills and turbines.  And sea captains have been known to use them to "power" sailing vessels.

Drearwigs are immune to the effects of temperature extremes, and take -2 damage per die from mutations like Energy Ray (Heat/Cold), Temperature Control, etc.

Mutations:  Control Weather, Energy Ray (Electricity)