Reflecting Pool

Reflecting pools are small pools of water used by Nimue, Merlina, and Knuckles the Echidna (in two separate canons). They were shown in Sonic and the Black Knight and the Sonic Underground episode "Friend or Foe?".

Sonic and the Black Knight
After Sonic the Hedgehog leaves for Camelot Castle, Merlina watches Sonic's progress using her reflecting pool. Nimue is shown to use a reflecting pool after all four barrier stones are activated. The pool shows map of Camelot, which indicates that the barrier formed is too weak. The last time the pool is used is before the battle between Excalibur-Sonicand the Dark Queen. In this scenario, the reflecting pool shows a strange ability, allowing the Knights of the Round Table to communicate with Sonic.

Sonic Underground
When Knuckles and Sonic were talking near a reflecting pool, Sonic mentioned that Sleet and Dingo would not leave the island so hastily; they were always looking for something. Knuckles suddenly realized that the two were after the Chaos Emerald themselves. He then caused the pool to create a column of water showing an image of the Chaos Emerald's location, discovering that Sleet and Dingo were in the process of stealing the Chaos Emerald from the island. Sonia describes the pool as a "Sacred Pool".