Bunnies

Bunnies is a anti-IC program designed by Wilson Wake, an enterprising 'runner who wanted to kill a Vampyre but didn't want to spring for Assassin software. When activated, Bunnies simply replicates itself, offering the Vampyre dozens of tasty subroutines to absorb. Since a Vampyre can only absorb 6 programs before automatically crashing, this program is very effective, if very specialized. The strength of the program represents the potential for initiating it before the Vampyre absorbs some other program.

Source

 * Chromebook Volume 1, pg.92