Scry vs Scry is a trope that refers to a particular type of fight scene that's often more talk than fight, as they jockey for position verbally and lay logic traps to catch the enemy in. It's not exactly a battle of wits as much as specifically a battle of prediction; trying to anticipate what will happen next, including your opponent's moves, while your opponent is trying to anticipate your moves knowing that you are already anticipating his.
The specifics of the trope depend on which of several categories the combatants fall into.
Prophets or Psychics:
This is a contest of wills and prophecy. The two characters making predictions of the future and how it will play out according to their desires and plans. Precognition, Scrying, Remote Viewing, Divination and the like are useful tools for this battle. The conflict may be a brief verbal showdown to "prove" who's the more accurate prophet, or it may be a generations-long struggle to control and manipulate the future. When all is said and done, everyone knows who wins, though their plans for victory might not see fruition for ages. This duel between psychics is the original concept of the trope, but as the TV Tropes Wiki points out, it has parallels in other genres…
The characters lay out their actions and counter-actions, talking through what they'll do, and possibly invoking the Wild Stalion Rule, like the final scene of Bill and Ted's Bogus Journey. Thanks to time travel, we don't have to wait for ages for someone to win, as a Time Machine facilitates resolving the plot at whatever speed is most exciting. The most likely outcomes involve one party ceasing to exist, or one party losing the ability to time-travel and becoming stranded in some inconvenient era of prehistory.
Masters of the Martial Arts:
Two badass martial artists stare each other down. In their minds, they plan their moves and reactions, size up their foes, and determine who is the true master. One bows to the greatness of the other (and perhaps commits ritual suicide for having been bested) — or they realize the battle will end in a stalemate or mutual death, so they decide not to fight after all. It's the kung fu equivalent of Mutual Assured Destruction.
With spell casters, this is likely to go beyond a mere test of wills or logic traps, even if both specialize in Divination or some sort of -mancy, they may have a few tricks that allow things to be pushed outside this trope. The predictions get backed up by that meddling that Wizards love to do, and the magic they can throw around to make it happen. If you have strictly-defined functional magic, then it's likely to be a Wizard Duel or just a fight scene with a lot of spells. If the game mechanics allow for looser improvisational magic however, you might get something more like a Shapeshifter Showdown, with new spells and enchantments being produced on the spot.
In an espionage game, two spies may engage is such a battle of wits over cocktails or dinner. In this variant, they fence verbally and reveal that the mole (spy) is actually a double-agent, who turns out to really be a deep cover triple-agent of Influence, but then it turns out he was actually discovered and fed false information by the Agent Provakateur, effectively rendering him an unwitting quadruple agent. Etc, etc. In other words, this battle isn't one of future planning or scrying, it's the revelation of things that have already happened off-camera.
Chessmasters or Magnificent Bastards:
Like the battle of wits between Vinzinni and the Dread Pirate Roberts over the drink spiked with iocane, this is a contest of wits, where two (or more) competitors try to ferret out the logic that drives their foes thinking, and penetrate their bluffs. The more you know your foe, the better prepared you are for such a battle.
A contest of rhymes or insults, either preceding or replacing a battle - very popular amongst our ancestors - particularly in periods where monomachia was also accepted practice. Also likely to be the mechanism of choice between professional entertainers and - in the form of a competitive debate - between theologians, academics and the like. Also popular amongst 20th/21st century yoof in the form of dance-offs and rap duels.
Based on their mention of Prophecy, Time Travel and Martial Arts, I extrapolated the spy and wizard implications.
Game and Story Use
- This sort of mental duel can empower non-combat characters to kick butt. It's like a battle using willpower instead of strength, magic and powers instead of weapons, and cleverness and creativity instead of combat skills.
- Throwing in a conflict like this is a great way to let the Mad Scientist, Prophet, Temporal Physics Professor or other mental-focused PC really shine in spotlight.
- It's also a way to test the enemy before the final conflict. Perhaps the villain schools the PCs, but lets them live. Of course, with a couple of bad rolls, this could backfire into a very short campaign, one way or the other. Make sure you're okay with all the possible results before you provoke a scene like this.
- These sorts of scenes have to be handled carefully, or else the fun gets spoiled by practicality.
- Most games have combat be a large number of rolls, and non-combat actions be a single "all or nothing" roll. That's probably not appropriate to this kind of duel, so you may want to think a bit about house rules or gimmicks to make the fight more interesting. Even "best two out of three" is more exciting than wrapping up the whole fight in initiative plus one attack.
- Players have a tendency to want to lead with their best move, which is contrary to dramatic tension. You may consider rewarding them (with XP, bennies, character points, drama dice, or the like) for every cool stunt or move, so that they're motivated to play around with it for a while.
- Don't forget to give the other PCs something to do if the scene runs long. You'd hate to have them get antsy and steal the thunder by just walking over and shooting the competition in a wretchedly anticlimactic fashion.
- The spy or magnificent bastards version might be a battle of charisma and connections instead of mind or muscle.
- For a "variant challenge" move the PCs into a position where they must win a public hustings against a demagogue - or rap well in front of gangstas to get access to what they want. See everyone who used charisma as a dump stat squirm.
- The Blue Men of Scandinavian myth could be driven off by defeating their leader in a rhyming battle - otherwise anyone accosted by them at sea would have a hard fight of it. Feel free to invent some modern, urban undead that can be rapped down …
- If your system allows it, a morale bonus at least would be a useful payback to a party or army whose spokesman wins a bardic duel before the shieldwalls meet.
- For the Bard character, winning a bardic contest at a major festival could be worth more XP than winning a battle.
- For the non-combat characters these sort of contests might make good side shows for a public games or tournament or even a form of disputation by someone other than a knight (for example a wizard might dispute a bridge against other wizards, calling on passers by to engage him in a contest of magical skill, a bard might dispute other bards to a contest of songs or poetry and a cleric might challenge with theological debate).