As noted above wild magic usually works best in authored fiction, instead of random game play.
So my method is to use my authorial power when a wild surge happens. A small set of guidelines, adjudicate or roll and press on with game/story.
I.e.
Consider what the spell was supposed to do...damage, control, transform etc.
Consider the level (maybe upcast or down cast by 1d4 levels) of the spell (have collateral damage always less than actual spell, charms change target, #of targets, or duration...etc.)
Think what would happen if that type of effect went awry...maybe roll even/odd for good effect versus bad effect.
Sleep: all creatures fail initial save. Or, effect/saves delayed one round (player doesn't know this)
Magic Missile: missiles hit random targets in range, or upcast/downcast by one level.
Detect Magic: lasts for an hour, or last for an hour then blind for 10 minutes. Or someone else gets the ability.
On the spot gives authorial power to describe the wild surge (much like the dm scripts or writes the action of the adversaries) so it works better for the story, like in fiction.
Just my thoughts.
So my method is to use my authorial power when a wild surge happens. A small set of guidelines, adjudicate or roll and press on with game/story.
I.e.
Consider what the spell was supposed to do...damage, control, transform etc.
Consider the level (maybe upcast or down cast by 1d4 levels) of the spell (have collateral damage always less than actual spell, charms change target, #of targets, or duration...etc.)
Think what would happen if that type of effect went awry...maybe roll even/odd for good effect versus bad effect.
Sleep: all creatures fail initial save. Or, effect/saves delayed one round (player doesn't know this)
Magic Missile: missiles hit random targets in range, or upcast/downcast by one level.
Detect Magic: lasts for an hour, or last for an hour then blind for 10 minutes. Or someone else gets the ability.
On the spot gives authorial power to describe the wild surge (much like the dm scripts or writes the action of the adversaries) so it works better for the story, like in fiction.
Just my thoughts.