Branched spark

A branched spark is an aberration that occurs every once in a million sparks. Instead of just one spark, two are produced, and the individuals that share the branched spark experience "vicarious perception", wherein pain felt by one can be felt by the another. They are also linked in life and death—if one dies, both die.

Fiction

IDW Generation 1 comics

Topspin and Twin Twist were a pair produced by a branched spark. Both frequently felt the other's pain, Last Stand of the Wreckers #3 and Topspin's sacrifice to activate Aequitas ultimately killed both of them. Last Stand of the Wreckers #4

Transformers Prime

Dreadwing and Skyquake had a branched spark as well. Dreadwing felt when his brother awoke from stasis on Earth, and when his spark was extinguished by the Autobots. For reasons unknown, Dreadwing did not fall to death as well.