Thief of Focus [Sleight of Hand]

Requires Perplexing Action Feat

When a creature within 5 feet of you casts a spell with material
components or an arcane focus which is held in its hand, you
can use your reaction to attempt to disturb the components
or focus to disrupt the casting of the spell. Make a Dexterity
(Sleight of Hand) check contested by the target’s spell save DC.
You have disadvantage if the target can see you. On a success,
you disturb the components or the focus in the creature’s hand
and it fails to cast the spell this turn. This does not expend the
affected creature’s spell slot. Once you use this feature, you can’t
do so again until you finish a short or long rest.

Next Rank /Legerdemain/