Counterspells, Magic Detection, and Dispelling

To be used as houserules or alternate class features

This one has been sitting in my drafts for a while. It is unfinished but I'm putting it out anyways because I likely won't finish it, and it might inspire someone.

Counterspells

'Counterspell' is not a spell in itself. It is a category of procedures applied to any given spell to make the spell simply not work. These can range from casting the opposite spell (Shatter vs. Mending, Fire vs. Water), to simply distraction (mundane or arcane), to stealing the energy of the spell. When a wizard or magically adept character sees a spell being cast, they can attempt a counterspell. Roll a contested check: on the countering side, d20+[Caster level]+[Spellcasting Score]; on the casting side, d20+[Caster level]+[Spellcasting Score]+[Spell Level]. The countering magician may use a spell to increase their bonus, adding the spell's level to the roll (or double the spells level for an opposite spell).

If the Caster wins, the spell prevails, and the counterspell possibly has a mishap. If the Counterer wins, they may consult the following table and choose one option in accordance with the difference in the rolls.

Difference	Effect
1	Deflect: The spell changes direction just before it reaches the target, up to 90 degrees
	Enfeeble: The spell falters, only producing half the effect
3	Distract: The caster makes a concentration check. If they fail, the spell wild-surges, explodes, mishaps, or dooms
	Rewind: The spell is returned to the caster, and any spell used to counter is also returned.
	Shatter: The spell splinters, dealing [spell level]d6 or [spell level] damage to its target
5	Negate: The spell does not work
	Awry: The spell has a different (but not opposite) effect. Fireball may become wind-ray, cure wounds becomes cured meats, etc.
7	Siphon*: The counterer absorbs the spell's energy, which may be stored in magic items or as spell slots
	Reverse: The spells effect reverses completely. Fireball becomes water-pseudosphere, cure wounds becomes cause wounds, etc.
	Reflect: The spell now targets the caster (or a random creature if it already targeted the caster)
9	Explode*: Choose a point on the spell's original trajectory. The spell explodes at that point, dealing [spell level]d6 damage in a [spell level]*5 ft. radius
	Doom*: The spell triggers a doom in the caster, or causes the worst possible mishap or wild magic surge.
11	Seal*: The caster can no longer cast magic for [spell level] (roll d[spell level]: 1. seconds 2. minutes 3. hours 4. days 5. weeks 6. months 7. years 8. decades 9. permanent)
	Steal*: The counterer learns the spell and the caster forgets the spell. As well, the counterer gains a temporary spell slot of the spell level.
	Unravel*: A wild-magic or null-magic zone is created around the caster
13	Death*: The caster is killed
	Magician's folly*: The caster is effected by a permanent effect, transfiguration, enchantment, or curse of the the counterer's choice, subject to DM discussion.

* these options also negate the spell

Magic Detection

Magic detection is, of course, not a spell either. Rather, it is a suite of tools, lore, mathematics, neuroses, and mutations that allow wizards to perceive the structure of spells, supernatural influences, and invisible creatures.

A knack will here mean a supernatural mutation, mnemonic device, or neurosis which may aid in detecting magic. A bauble is a physical tool such as a lens, crystal, or fetish which helps one do the same. Certain divination spells may also assist. Familiars may also help.

Knacks and Baubles have certain intended targets (e.g. fairy magic, divine magic, fire magic, etc.). Both have a 1 in 2 chance of positively identifying influences of that type, a 2 in 6 chance of positively identifying neutral magic, and a 1 in 4 chance of correctly detecting magic of a very different type. As well, both have a 1 in 6 false positive chance. Divination spells have a flat chance (1 in 4 for cantrips, 2 in 6 for 1-4 lvl, 1 in 2 for 5-7, 4 in 6 for 8-9. 1 in 10 false positive for cantrip-4th lvl, 1 in 20 for 5-9).

Knacks may be used quickly (in 1 round), but the use of a knack deals 1 wisdom damage and prompts a save vs. wizard eyes. Baubles take 1d6 rounds to find, set up, and use, but do not have any ill effects. Divination spells of course take a spell slot. Multiple tools may be used in succession, and this is recommended.

[Example: Algol the Hidden has 2 baubles and 1 knack: A quartz orb (detects wizardry), a sorcerer's mask (detects spirits), and a third eye (detects dark magic). While travelling, they encounters a man they suspect is a werewolf (he, in fact, is). They first examine with the mask (werewolves are acceptably close to spirits, 2 in 6). They looks through their mask and sees a fearsome, if ethereal, wolf form over the man! Or wait, maybe that's a trick of the light, or simply a wolf spirit, since it soon passes (in fact, it was a false positive and has no bearing on the man's nature). 

Algol, now unsure, looks through their quartz orb (werewolves are very different than wizards, 1 in 4). Nothing comes of this. Maybe he isn't a werewolf? Greatly concerned, Algol peers with their third eye (a discussion of whether werewolves are dark magic ensues. It is decided they are. Also, Algol suffers 1 Wis damage and makes their save for Wizard Eyes). Algol sees the stain of death on his teeth and the wicked claws of his true form! They were right! After a small skirmish, the man is justly imprisoned.]

Wizards begin with 2 baubles and 1 knack. Sorcerers and Warlocks begin with 2 knacks and 1 bauble. Knacks may be gained from magical deals, maddening texts, and certain potions. Baubles may be purchased from other wizards, crafted with special ingredients, or stolen. Some baubles may be used by mundane characters.

Some Baubles

1. Erratic Clock (Chronomancy)
2. Magician's Pendulum (Magic Items)
3. True Quicksilver (Necromancy)
4. Otherworldly Ring (Planar)
5. Elemental Barometer (Elemental)
6. Scope of Many Lenses (Wizardry)
7. Shamble (Witchcraft)
8. Phantasmagoric lantern (Illusion)

Dispelling

Technically, dispel magic is a spell. The spell is a brute force form of a more general principle: spells may be disrupted by altering the delicate but mundanely untouchable structure of a spell. This is easier and more graceful if the dispeller knows the workings and nature of a spell (found by magic detection or guessing)