Weave Entanglement

6th-level abjuration

Casting Time: 1 action
Range: 90 feet (20-foot-radius sphere)
Components: V, S, M (a piece of felt)
Duration: Concentration, up to 1 minute
Class: Bard, Sorcerer, Wizard

You imperceptibly tangle the threads of the magic in a 20-foot-radius sphere centred on a point you can see within range. Whenever a creature attempts to cast a spell of 1st level or higher in this area, it must make an ability check with its spellcasting ability against your spell save DC. On a success, the spell is cast as normal. On a failure, the spellcaster casts the spell and produces an additional effect. Roll a d10 and consult the following table to determine the additional effect:

d10	Effect
1	The spellcaster casts Gravity Smash
2	The spellcaster casts Phantasmal Force.
3	The spellcaster casts Confusion.
4	The spellcaster casts Fireball.
5	The spellcaster casts Zippit!.
6	The spellcaster casts Web.
7	The spellcaster casts Darkness.
8	The spellcaster casts Silence.
9	The spellcaster regains 2d10 hit points.
10	The spellcaster doesn’t expend a spell slot to cast its spell.

Any additional spell cast this way targets or is centred on the spellcaster, who has no control over the spell’s effects. The DC for any saving throws equals the spellcaster’s spell save DC In the case of concentration spells, no concentration is required. At initiative count 20 of each round, roll a d20 for each ongoing additional effect. On a roll of 11 or higher, that effect ends.

At Higher Levels. When you cast this spell using a spell slot of 7th level or higher, you increase the radius of the area affected by 10 feet for each slot level above 6th.

Source: Heliana's Guide to Monster Hunting