Spellstealer's Wand

When the wielder or an ally within 5ft becomes
the target of a spell, the wielder can use a
reaction to subtract 1d4 from the spell hit roll or
add 1d4 to a spell save. On a miss or successful
spell save when this reaction was used, the wand
gains 1 charge of the spell used.
Wielder can spend 1 charge to cast the stored
spell for free, using their spell casting modifier.
Max 1 charge.