Trident is a mysterious object found by Zac Blakely. It looks similar to Poseidon's Trident from myth and it can control lightning drain the life force of mermaids, detect Invisibility, and possibly can do more. In "Zac Returns to Mako", Zac takes a portal from Trident Cave into the ocean that has the Trident in it, but he leaves before he can grab it. In "Betrayal", Zac takes a portal from Trident Cave into the ocean and grabs it, but Lyla tries to take it away from him. When mermaids touch it, it sparks out of control and kicks everyone out of the portal. Zac was under the influence of the Full Moon and when he touched the Trident he snapped out of it.
In "I Don't Believe in Mermaids", Rita Santos reveals that a pod of mermen took the Trident into battle and the mermaid pods had to draw upon the power of the oceans to defeat them. The Trident was locked away to prevent a similar situation from happening.
- In center of the pronged area appears to be a larger version of the stones in the Moon Rings.
- From what it seems from the episode Betrayal, when a mermaid touches the trident it sparks uncontrollably and repels them from itself.
- The Trident had a similar affect on Zac as the full moon has on him, it drew him in, so he could wield the trident.