Starscream can now either:
a/ Possess Soundblaster's body

"Starscream's never give up attitude extends even to the afterlife: unlike most Transformers, he has a mutant, indestructible Spark. His life-force cannot be destroyed and can persist even without a body to contain it."

"Additionally, Starscream's spark was able to take possession of other Transformers simply by entering their bodies. While in another body, Starscream's will completely dominates that of his host."
http://tfwiki.net/wiki/Spark#Starscream

b/ Return as an undead zombie and eat Soundblaster's cerebral circuits. NOM! NOM! NOM! NOM! NOM!

"his shattered husk was reanimated by the residual energy of the Underbase that still saturated it, and driven by Starscream's own muderderous impulses into an insane rampage."
http://tfwiki.net/wiki/Race_with_the_Devil

http://tfwiki.net/wiki/Starscream_%28G1%29