Magico: "What's this? Normally I have to chase my prey, but here are four cute mermaids right at my doorstep."
Veronica: "It's not us that are the prey this time, fish face."
Magico: "Well aren't you a gutsy one? I will enjoy breaking you."
Natalie: "We aren't mermaids, Magico! We are Magical Girls sent to defeat you!"
Magico: "Oh, they recruit mermaids nowadays? Then let's see what you're made of!"
Eric(a): "Does anybody know what kind of Magico she is?"
Natalie: "No, usually Isabelle takes care of that, but I don't think she can reach us here."
Wendy: "That is an aquatic spell caster Magico. This particular kind of Magico specialises in magical attacks and mind control. That eye in the tip of its tail is used to both hypnotise its victims and drain their mental energies. Once they are too weak to feed the Magico, it transforms them into mindless minions. The code name for this kind of Magico is Mindstinger."
Eric(a): "Wendy!? How do you know that?"
Wendy: "I do not know, it just came to my mind."
Veronica: "Focus, minion! We are in the middle of a fight, this is no time for day dreaming."
Eric(a): "Oh sorry, you're right. Just one thing: try not to look at the eye in the tip of her tail."
| HP | MP | ATK | DEF | MAT | MDF | AGI | LUK | EVA | NUL |
|---|---|---|---|---|---|---|---|---|---|
| 2500 | 140 | 26 | 18 | 30 | 29 | 32 | 37 | 10% | 0% |
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|---|---|---|---|---|---|---|---|---|---|---|
| - | - | - | - | Wk | Rs | Wk | - | Wk | Im | Im |
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|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Wk | Im | Im | Im | Im | - | Im | - | Im | Im | - | - | - | - | - |
Spells and Abilities:
- Cold Flames
- Doom Bolt (requires Focus)
- Drain the Thralls
- Gaze of Domination
- Magic Bolt
- Mind Drain
- Shatter Magic
- Shimmering Ward
Drops:
- 600 lumes
- Water Core
Mindstinger is the magico boss of the Mermaid Caves.
True to her name, Mindstinger's capabilities lie in toying with the minds of her opponents. Gaze of Domination is a mainstay of her kit, allowing her to inflict Charmed (Strong) on one of your party members. Leaving anyone Charmed in this battle is extremely unwise - not only will they spend their turns attacking their own team, they become susceptible to Drain the Thralls, a move which siphons MP from charmed units in order to heal Mindstinger dramatically. Any time a party member becomes charmed, quickly use a Seal of Focus to restore them to sanity.
The core mechanic of this fight being a status effect would lead one to think Lovely Barricade and 
Ailment Guard would be a key counter, but the use of it will make Mindstinger cast Shatter Magic immediately afterwards to get rid of it. Theoretically though, this could actually be taken advantage of to keep her locked from using other skills during her turn, albeit at the cost of 15 MP and Eric(a)'s turn.
Beyond that, Mindstinger is a fairly straightforward opponent. She'll pelt your party with Ice and non-elemental damage, but not in especially massive amounts. If she uses Focus, guard the next turn to prevent her Doom Bolt from likely one-shotting one of your characters. If she throws up a Shimmering Ward, avoid casting attack spells if you have alternatives until the status effect expires. So long as you deny her the ability to drain your team for healing, she shouldn't last terribly long.
Losing the Battle
If you are defeated by Mindstinger, Eric(a) will be subjected to the magico's mind-shattering powers long enough to permanently lose 5 MDF. The ensuing events will lead to the Mermaid Caves being destroyed and Eric(a) receiving a level of the Penis Reduction Transformation. Unlike most bosses, there is no way to challenge Mindstinger again after a loss, meaning the MDF and Water Core are both lost forever.