Eye Theft with the Scalpel

Dojutsu can be taken from other shinobi, or from yourself, with a scalpel and a tense timing duel.

The Scalpel

An item that stacks to 1. Tooltip: "Use on a badly wounded shinobi (20% health or less) to extract an eye. Sneak and use to extract your own. Breaks after one attempt."
Hold it in your main hand and right-click another player. Only players can be targeted.

Conditions

Only a dojutsu can be taken: a Sharingan, any Mangekyo or the Byakugan, whether the victim's own or implanted. Never a plain eye or an empty socket.
Each socket is judged on its own (one can hold a dojutsu and the other not). With nothing to take: "They have no dojutsu to take."
The victim must be at 20% of their max health or less: "They're still too strong: wear them down first (20% health)."
The victim must not be eye-guarded (see below): "They fought off an attempt recently: X min until their eyes can be taken."
Neither player can already be in an extraction.

The Timing Duel

The duel starts with a trident-hit sound, and the victim is told "<thief> is going for your eye! Press the keys in time to fight them off!"
Both players are held in place (Bound) for the whole duel.
A bar across the top of the screen shows both players the eye and side; the victim's GRIP on the left (their hit rate so far) and the EXTRACTION on the right; in the middle, the key to press with a ring closing on it; and "Round x/y". Roles are shown as "Extracting", "Defending" or "Extracting your own eye". The world isn't paused or hidden.
Each round lasts 1.6 seconds. A random key from W, A, S or D is shown, and a ring closes on it, meeting the circle at 1.0 second.
A press counts only if it's the right key between 0.7 and 1.3 seconds into the round, and is "perfect" between 0.9 and 1.1 seconds. Each player gets one press per round; later presses are ignored.
Thief: a good press adds 22 to the extraction, a perfect one 30. A wrong key, a press outside the window, or no press at all costs 4.
Victim: a good press removes 13, a perfect one 18. A miss costs the victim nothing.
The extraction stays between 0 and 100. A bell rings for a hit (higher for perfect) and a bass note sounds for a miss.
A duel against another player lasts 10 rounds.
The duel is called off (and the scalpel breaks) if either player dies or leaves, they get more than 8 blocks apart, or the thief stops holding the scalpel in the main hand.

Winning and Choosing the Eye

Extraction reaching 100 wins the duel. The thief then has 5 seconds to pick the LEFT or RIGHT eye on a choice screen ("Take which eye from <name>?") showing what each socket holds. Sockets showing "Empty" or "Plain eye" can't be picked.
Too slow: "Too slow: the scalpel's wasted and they keep their eye."
Picked: the eye comes out with a wet tearing sound. The thief gets a jar ("You took the <eye> of <name>."). The victim takes 2 damage, is blinded for 5 seconds, and is told "Your <eye> was taken."
The scalpel breaks either way, win or lose.

Eye Guard

If the rounds run out before the extraction is full, the victim has fought it off: "You fought them off! Your eyes are safe for an hour." Their eyes can't be targeted for 1 hour of game time. The thief is told "<name> fought you off. The scalpel broke."

The same 1-hour guard also starts after a successful theft, so a player who has just lost an eye can't be targeted again straight away.

Extracting Your Own Eye

Sneak and use the scalpel (right click in the air) to extract your own dojutsu. It's the same duel alone, against time: 8 rounds, a good press adds 25, a perfect one 34, and a miss (or no press) costs 10.
Winning, you pick your own left or right eye ("Extract which of your eyes?").
Success: your eye goes into a jar; you take 4 damage and 5 seconds of blindness ("You extracted your own <eye>.").
Failure: "Your hand slipped. The scalpel broke." and 3 damage.