Light of the Full Moon
Taking the charge of Moon Rings
Drains without the light of Full Moon
Destroyed (by Zac Blakely)
The Trident is a mysterious object found by Zac. It looks similar to Poseidon's Trident from myth and it can control lightning, detect mermaids by glowing when one is near, drain the strength out of mermaids, drain Moon Rings as well as reload them, and possibly can do more.
In I Don't Believe In Mermaids, Rita reveals that a pod of mermen took the Trident into battle and it took the strength of all mermaids from the five oceans to defeat them. The Trident was locked away to prevent a similar situation from happening. In Trust, Lyla reveals that the mermaids survived the war with the mermen because one merman knew the war was wrong, so he took the Trident and locked it away in the Trident Cave, where it could never be used again.
In Zac Returns to Mako, Zac opened a portal from Trident Cave into the ocean that has the Trident in it, but he left before he could grab it. In Betrayal, Zac opened a portal again, but this time he grabbed it, however Lyla tried to take it away from him. When the mermaids touched it, it sparked out of control and kicked everyone out of the portal. Since Zac was under the influence of the Full Moon, he snapped out of it with the blast. In The Trident Job, Zac beat the mermaids to the trident Cave and successfully retrieved the trident. In Where's the On Button, Zac and Cam discovered that the Trident was powered by moonlight, the same power that power the mermaids' moon rings. In Zac's Choice, Zac discovered that the Trident can potentially kill a mermaid, after he and Lyla fought over it, so he locked it back into the Trident Cave to prevent anyone else from being hurt in the future. Cam Mitchell used Nixie's trust to get into the portal and took the Trident for himself, with an intent to become a merman. In Decision Time, the trident was destroyed after Zac used telekinesis to smash the trident against the Moon Pool wall.
In season 2, an illusion of the trident appeared when Zac activated the mystical Merman Chamber. This illusion signified that the trident was needed to activate the chamber. It is later revealed that after the trident was smashed, Sirena hid the trident's moon stone at Rita's grotto. It is also revealed the trident's power source was the moon stone. Although it had apparently lost it's power when the trident was destroyed, it became active and dangerous again after Zac touched it due to his stronger connection to Mako meaning that although the body of the trident was destroyed, the heart of the trident's power was still functional. This meant it could be used to fully activate the chamber. Erik finds the stone and uses it to activate the chamber, causing the stone's power to be amplified and to drain life-forces from mermaids. Zac deactivates the stone almost at the cost of his life before his sister, Mimmi, used the stone to heal him, turning the relic to ashes in the process and ending the threat of the trident once and for all.
Throughout it's appearances, the trident appeared to have some form of artificial intelligence. It seemed that the trident would operate for anyone who used it for it's intended purpose to destroy mermaids. When Zac claimed possession of it, it activated for the first time during a confrontation with the mermaids by draining magic from the Sirena's moon ring. In "Nowhere to Hide", the trident activated on it's own and began to drain Rita's life force despite her not being in direct contact with it as she attempted to convince Zac to put it back in the trident chamber. This was possibly the trident trying to silence Rita and stop her from getting Zac to give it up. Later, when Cam claims the trident after Zac put it back and attempts to take it to the moon pool, Zac attempts to take it from him only for the trident to turn on it's former owner and knock him unconscious so Cam could proceed with his plans. This artificial intelligence appears to have remained when the trident itself was destroyed and only the stone remained. In "The Trident Stone", the stone attempts to urge Zac to use it to activate the chamber. When Erik claims it, the trident stone steals Zac's powers so that he can use it instead, reinforcing the idea that the trident would serve anyone who uses it to destroy mermaids whether that be their intention or not since Zac merely wanted to use it how he saw fit when he possessed it and Erik thought the chamber had potential to do good things when he used the stone to activate the chamber.
- Electrokinesis - The Trident has the power to control lightning.
- Mermaid Detection - It has the power to detect mermaids by glowing whenever one is near.
- Invisibility Detection - It also has the power to see and detect invisible mermaids.
- Mermaid Life-Force Draining - It also has the power drain the life force of mermaids just by being near or touching it.
- Reloading and Draining Moon Rings - It also has the power to reload and drain the Moon Ring's power.
- Legs Spell - Mermen can perform a spell to grow legs, but that kind of magic is possible only on Full Moon. As the Trident store the light of the Full Moon, the merman who has the Trident need not wait until the full moon to grow legs. The legs are equal to that of humans who have been turned into mermaids by magic: while dry they have legs, but as soon as the water hits them they grow tails. It's not known if this spell is reversible, but most likely is.
- Rain Stopping - Mermen can cast a spell to stop the rain.
- Hydro-Thermokinesis - Mermen can cast a spell to melt ice and presumably snow.
- Healing - The Trident has the power to heal.
- Chlorokinesis (Plant Manipulation) - Mermen can cast a spell to grow/manipulate plants.
- Coma - The Trident also has the ability to put people into a type of coma.
- Force Field - It could be used to provide a magic shield/force field.
- Enlargement Spell - Mermen can perform a spell to enlarge an object.
- Shrinking Spell - Mermen can perform a spell to shrink objects.
- Duplication Spell - Mermen can perform a spell to duplicate matter in number.
- Sleep Spell - Mermen can perform a spell to make someone fall asleep.
- Containment Spell - Mermen can perform a spell to contain things.
- Trapping Spell - Mermen can cast a spell to trap a creature.
- Adapting Spell - Mermen can perform a spell of adaptation.
- Incineration - Mermen can perform a spell to incinerate objects.
- Object Manipulation - Mermen can perform a spell to manipulate objects.
- Cyrokinesis - Mermen can perform a spell to freeze objects.
- Levitation - Mermen can perform a spell to make objects float in midair.
- Remote Spell - Mermen can perform a spell to cast a spell on someone or something from a distance.
- Accelerated Growth Spell - Mermen can perform a spell to accelerate the growth of something.
- Storm Spell - Mermen can perform a spell to summon a powerful and strong storm full of thunder and lightning.
- The trident has the same moonstone as the Moon Rings, just bigger and a hundred times more powerful.
- Like the Moon Rings, it only works where it can receive the light of the Full Moon.
- To recharge it has to be exposed to the light of the Full Moon, or it will drain.
- The trident can suck the energy out of Moon Rings, leaving the trident loaded and exhausting the rings.
- Just as the trident is able to remove the power of the Moon Rings, it can also recharge them.
- It was made to neutralize everything that mermaids do.
- If it is brought into the water of the Moon Pool on the night of the Full Moon, it will destroy the Moon Pool and the mermaids' source of power.
- It is unknown why the Trident moonstone only drains the power of mermaids. It could be a mutation of the normal moonstone or a spell cast by mermen. Presumably, there could be a version of this stone that only affects mermen and leaves mermaids immune.