Rescue Squad (レスキュー Resukyū) is a series of Level 4 EARTH Beast monsters with 300 ATK and 100 DEF. Each of the monsters focuses on Summoning monsters in different ways from the Deck, with the intention of using them to Summon the newest types of monsters.
All members of the Rescue Squad series' artwork feature their namesake animal wearing gear commonly associated with public safety workers, such as a whistle or a harness, and a hardhat. They are also always seen standing against a sky blue background, though it is often appears more white in color due to the foiling of the card.
Ironically, the members of the Rescue Squad series aren't meant to work together. Rather, they are meant to facilitate the use of whatever new Summoning method is being introduced at the time, as the mechanic is typically still in its early stages and lacks wide support. To do this, they Summon monsters from the deck, which are destroyed during the End Phase.
After the original member, "Rescue Cat", who is often used with Synchro Summoning strategies, "Rescue Rabbit" was released early in the Yu-Gi-Oh! ZEXAL era to aid in Xyz Summoning; "Rescue Hamster" was released early in the Yu-Gi-Oh! ARC-V era to aid in Pendulum Summoning; and most recently, "Rescue Ferret" was released early in the Yu-Gi-Oh! VRAINS era to aid in Link Summoning. In VRAINS, the Rescue Squad series also gained its first support card, "Emerging Emergency Rescute Rescue", meant to further speed up the Summoning effects of the monsters by searching them more easily.