Arcane Bug

The arcane bug allows the caster to hear conversations through a tiny device, the caster can even hear communication magically sent to the target from spells 3rd level or lower like message or sending. 

The caster must first enchant the tiny bug and ear piece by casting this spell as a ritual, binding the caster to the items.  The caster may only be bound to one bug and ear piece at a time.  For the spell to monitor magical communication, the tiny bug replica must be within 1' of the target creature. 

If placed on an item or clothing currently worn by the target, the the caster must make a slight of hand check using their spell casting ability (DM may assign advantage or disadvantage based on the situation).  The bug has a strong adhesive that will prevent it from falling away without a determined effort.  While the caster and target are on the same plane, the caster may recast this spell and listen through the ear piece as if their ear was in the position of the bug (Perception rolls use spell casting modifier). 

The bug is magically difficult to see (Spell casting DC to spot with a disadvantaged Investigation check) and can only be spotted with detect magic if cast at the same level or higher as the "Arcane Bug" spell.

When cast at higher level: The bug may listen to magical communication that is one level lower than the spell slot used (e.g. listening to an 8th level Telepathy spell requires casting Arcane Bug using a 9th level slot).  If cast as a ritual, the spell level will always be 4th.

"There were times I felt like she knew too much, almost like she could hear my most secret communications"