Screechwing
Screechwing is an Maximal in the Beast Machines portion of the Generation 1 continuity.
Screechwing is a mystery.
Around December of 2000, the online retailer Big Bad Toystore put up a list of upcoming Transformer product from Hasbro. Although the main point of interest was a Transtech assortment listing, there were several tail-end and unreleased Beast Machines: Battle for the Spark toys mentioned as well.
Two basics listed as coming out after March of 2001 were Screechwing and Spiketail. Screechwing is described as "redeco bat".
Presumably, Screechwing was to be a redeco of Sonar, the Transmetal 2 bat from Beast Wars. However, with the early demise of Beast Machines, the complete retail abortion of Transtech, and the importation of Car Robots as Robots in Disguise, Screechwing never saw the light of day.
