However , he acquired new scars after a fight with a Pak protector in The Ringworld Engineers .
After involuntarily receiving an injection of the Kzinti analog of boosterspice , his scarring gradually disappeared .
He acquired new scars after a fight with a Pak protector in The Ringworld Engineers .
After involuntarily receiving an injection of the Kzinti analog of boosterspice , his scarring gradually disappeared .