The seeker is a reconnaissance device developed by the Xindi-Reptilians originally for use in the Xindi Civil War. It incorporates antigravity technology to fly and seek enemies and then report back to its operator. It, like much other Xindi technology, incorporates biological components; so much that a Starfleet scanner could actually mistake it for a Xindi biosign. A seeker also incorporates the same kind of subspace vortex equipment used by Xindi ships, although it is used on a smaller scale.
The Reptilians attempted to use a pair of seekers to locate Gralik Durr on the Xindi-Arboreal colony, but they were destroyed by Enterprise personnel. (ENT: "The Shipment")