Here's a sketch I've recently dug out, originally created a few years back. This design never went any further than what you see here - its form of locomotion was not particularly well conceived. But, ignoring that, I did actually write quite a bit of technical blurb to go with it:
The ‘Terrain’ or ‘T’ variant of the K-generation ‘Stalker’ Bio-Robot was introduced as a stealth mechanoid with the agility and speed characteristics of a Panther (it‘s developmental code name was ‘Cat’). Seen here in it’s ‘raw’ guise, the T-K-1’s party-trick is achieved through light-bending surface ‘plates’, allowing the robot to all but visually disappear into it’s surroundings. Unfortunately this technology is very susceptible to damage; any malfunctioning light-plate will produce an ‘image tear’ in the robot’s surface, exposing it to it’s environment. In addition, small, localised EMP charges temporarily jar the robot, and disable the signal to these plates, again exposing the robot. Such occurrences normally only last 1-2 seconds, before the robot’s CPU resets the image feed.
Over 1.5 metres in length, and able to reach speeds in excess of 60mph, the T-K-1 is known as a ‘hit and run’ mech; many of it’s victims never even see or hear it approaching. It is designed to adapt to a variety of payloads (carrying over 40kg has been known) depending on terrain and mission requirements. It’s most common setup consists of an electric-plasma turbine mounted at the rear of the main body, which provides additional acceleratory thrust in addition to the robot’s four legs. Intelligently controlling the unit is a Dual-Bio-Tech CPU (Uto-Technologies™ revolutionary organic/electronic processor), which can regenerate its power-supply to 100% within 2 hours (when at rest) via it’s solar-capacitors (mounted atop it’s head)*.
Many T-K-1 Stalkers are fitted with a ‘Scavenger’ unit; a much smaller mechanoid (no more than 30cm in length) that is concealed within the Stalkers undercarriage. This Scavenger is deployed when the T-K-1 either meets an obstacle it can no longer navigate beyond, or when it wants a vantage point perspective of a target without having to break cover. Although this Scavenger is a separate unit, it is still a component of the T-K-1 Stalker’s AI; they are one in the same ‘entity’.
•NB: Due to the lack of consistent sunlight available in many environments, the Stalker seeks sources of artificial-light (eg street lighting) to recharge itself, although such locations inherently come with the risk of exposure to others (as their camouflaging light-plates have to be inactive for charging to take place).