It is a miniature Vulcanian/Gnomish device, about the size of a small house, mostly made of wood covered with metal plates, and mounted on four short and sturdy legs. It is designed to look like an angry rhino, with steam hissing out of its nostrils and a deep rumble coming from its innards (the gnome's steam-powered engine inside). MV 90' (30').
The Schreckmaschine has a natural AC of 0. Non-magical damage from hand-held weapons (including damage from arrows and crossbow bolts) receives a -6 pts penalty. Structural damage from siege weapons and all magical attacks apply normally. Because of the schreckmaschine's size and slow movement rate, all missile attacks receive a +2 bonus to hit. A typical schreckmaschine has 100 hp.
It's main attack is the metal horn in the front which can swing to gore and batter a foe. The schreckmaschine makes one attack every two rounds -- Dmg 3d6+2 vs. normal creatures, 3d10+2 vs. large creatures, or 1d6+8 structure damage. The horn can otherwise be used as a normal battering ram and is powerful enough to count as a magical weapon as far as hitting magical creatures goes.
The schreckmaschine can also release a cloud of steam, inflicting up to 6d6 points of non-magical heat damage within a 30' radius. If so, the schreckmaschine moves at half-speed and attacks with a -2 attack penalty until steam pressure is re-established, 2d4 rounds later. If it releases steam in a second attack before pressure is re-established, the entire machine goes dead for 2d4 rounds (etc).
The schreckmaschine saves and attacks as a 5 HD creature, provided there is at least one crew member inside to manoeuvre the mechanical horn. Another is needed to handle internal machinery, one more for driving, and a fourth to command the crew. The schreckmaschine gains one "HD" for each of the extra crew, plus another if the crew includes either Vulcanian gnomes or trained Heldannic Knights -- i.e., with a full trained crew, it is considered a 10 HD monster.
While "buttoned up" inside the schreckmaschine, the crew is protected from outside damage. Any damage beyond the device's own 100 hp applies to the crew, as appropriate to the attack. The commander typically is a priest level 7 or higher. The only magic, aside from the gnomes' internal machinery, is a permanent spell to keep the inside of the schreckmaschine cool, an important consideration while operating in Davania.
Heldannic Knights are presently working on the Schutzmaschine (or Mk.II),
which is comparable to the Mk.I, with some exceptions. It does not have the
mechanical horn. Instead it has a closable slit in the front allowing a light
ballista to shoot incendiary javelins. The Mk.II is a bit larger and fits up to
four knights and their horses, or twelve footmen, in addition to the crew. A
large opening can be released quickly in the rear to allow the troops in/out.
Neither machines are amphibious, however, and are particularly vulnerable to
soft terrain (mud will immobilise schreckmaschinen, while sandy or forested
terrain will halve their movement speed).