Scrap Drake Converted for B/X

I'm planning to finally start a B/X campaign so I've been going through some PDF's I have laying around. Inside of Kobold Press' Monsters of Sin: Sloth has a good chunk of ones I like a lot, including the Scrap Drake.

However when I went to convert it I realized that I couldn't find Drakes anywhere until 3.5...so I had to grab a few books and figure out how best to do this. Here's my attempt:

SCRAP DRAKE (B/X Conversion)

Perfect photo sent to me by Zak Smith of what it should totally look like

AC 4  ||  HD 5+1*  ||  Move 30'/15'  ||  Save as Fighter 5
THAC0 14  ||  Senses: Infravision 60', Low Light  ||  Surprises on 4 out of 6

Attack: Bite 2d8, Tail Slap 2d8
Special: Improvised Breath Weapon (20' cone, damage equal to health remaining; move to load, standard to attack)
Special: Burst of Speed: Every 3 rounds the Scrap Drake can wrench its bulk from the floor and run on its legs, gaining +1 to attack rolls and -1 to AC (AC 3), as well as moving double speed for a single round.



The Scrap Drake is the bottom of the bottom of dragons, a lesser drake. Lazy to the core, a Scrap Drake lays in one spot for so long it often ends up covered in fungi and lichens and dust and rocks enough to camouflage it. As they prefer to lay about, they usually will eat whatever comes near and is not very picky. Having no breath weapon it will gather rocks and dungeon junk around it in its mouth and spew it out at unsuspecting victims. 

The Scrap Drake prefers to wriggle on its belly rather than walk on its two hind legs and grows about 10' long and can weigh around 2,000 pounds.