Back in the day, White Dwarf magazine was the British answer to the Dragon, and its regular "Fiend Factory" column was a source of many monsters for early D&D games. In fact, the first edition Fiend Folio (1981) was largely a collection of monsters submitted to WD. This 3e conversion is part of an ongoing project to resurrect some interesting WD monsters that, for one reason or another, fell by the wayside. The Tenser beast was a submission of J. D. Morris; it appeared in White Dwarf 16 (December 1979/January 1980) , in a special Fiend Factory installment that detailed monsters that very nearly made it into the Fiend Folio -- complete with line art by some of the iconic Fiend Folio artists.
A glowing, rapidly-spinning disc hovers in the air before you.
Always N Tiny construct
Init +4; Senses darkvision 60 ft, low-light vision; Listen +0, Spot +0
AC 21, touch 18, flat-footed 17
(+2 size, +4 Dex, +3 natural, +2 deflection)
hp 11 (2 HD)
Immune construct traits
Fort +0, Ref +4, Will +3
Spd fly 50 ft (perfect)
Melee blade +7 (1d4 force/18-20 x3)
Space 2.5 ft; Reach 0 ft
Base Atk +1; Grp -11
Atk Options augmented critical, magic strike
Abilities Str 10, Dex 19, Con -, Int -, Wis 10, Cha 10
Feats Weapon Finesse B
Environment any
Organization solitary or guard (2-4)
Treasure none
Augmented Critical (Ex) The Tenser beast's blade threatens a critical hit on a natural attack roll of 18-20, dealing triple damage on a successful critical hit.
Magic Strike (Su) If the Tenser beast hits with its blade attack, the attack is treated as magic for the purpose of overcoming damage reduction.
This unusual construct is a pure creation of magic, being simply a flying, spinning disk of force. Tenser beasts can only obey a limited set of commands, and are usually deployed as guards or traps.
The edges of the spinning disk are extremely sharp, and the Tenser beast will dart in to cut opponents to ribbons. As a force effect, its blade extends into the Ethereal Plane and can affect incorporeal creatures.
Constructing a Tenser beast requires highly specialized manipulation of raw arcane forces and a DC 28 Spellcraft check. Caster Level: 13th; Prerequisites: Craft Construct, animate objects, floating disk, haste, keen edge, mage's sword; Market Price: 3,000 gp; Cost to Create: 2,500 gp + 80 XP.