Choose one ongoing magical effect, such as a persistent effect created by a concentration spell, that you can see within range. If it was created by a 2nd level spell or a cantrip, you gain control of it and it is now maintained by your concentration rather than its original caster’s. (You may redefine parameters chosen by the original caster upon their casting of the spell.) If the effect was created by a spell of 3rd level or higher, make an ability check using your spellcasting ability. The DC equals 12 + the spell's level. On a successful check, you gain control of it.   If you lose concentration before the spell ends and the original caster can still see the effect, they may make a contested ability check using their spellcasting ability versus your spellcasting ability. If they succeed, they regain control of it. Otherwise, the spell ends as normal. (If the effect is created by an object or artifact, the object or artifact automatically succeeds on the check.)