This card is used to Ritual Summon "Transonic Bird". You must also Tribute monsters from your hand or field whose total Levels equal 4 or more. The Level of the monster Special Summoned by this effect becomes the total Levels of monsters used for its Ritual Summon. You can banish this card from your GY, then target 1 Ritual Monster you control; send 1 Ritual Monster with the same Type or Attribute from your Deck to the GY. You can only use this effect of "Sonic Tracker" once per turn.