The Sonic Summoner is an optional gadget in Ratchet & Clank. It is a helmet that summons sand mice from the ground when found, which float in craft and fire bullets at enemies.
The Sonic Summoner device uses a hypersonic pulse emitter to produce a sound wave at just the right frequency that attracts a sand mouse, aliens which live underground and float in a tiny craft. When wearing the helmet near a sand mouse's house, the sand mouse comes out and hovered by Ratchet's shoulder for a moderate duration of time, shooting any enemy within its range. Sand mice are found on almost every planet.
Behind the scenes
The original sand mice summoned could not fly; it would reward Ratchet with a lump sum of bolts upon meeting it and would sometimes require the player to walk it to another sand mouse house before presenting a reward.