|Your name's Percival?|
Nefarious Dropships were larger and improved versions of the Tyhrranoid Dropships. They were mostly yellow with silver and orange. They attacked Ratchet with orange beams and had more health and did more damage than the originals.
They could occasionally be seen flying around in the air on several planets; however, Ratchet was attacked by several on Koros.
Before the release of Ratchet & Clank: Up Your Arsenal, they were on every planet in place of the original Dropship and would drop enemies; however, they were replaced with the original and limited to Koros. This can be seen on an IGN pre-release video, here: 
- Ratchet & Clank: Up Your Arsenal (first appearance)