Quickling's Ivy

Rare, Requires attunement
+1 Rapier, 1d8+1 piercing damage, +1d4 poison damage, finesse weapon
2/times per short rest - Ensnaring ivy, when landing a successful hit you may choose to cause the blade to instantly sprout a tangle of ivy vines.  The target must succeed on a strength saving throw DC 16 or become restrained for 3 rounds.  They may attempt another save at the start of their turn.
On scoring a critical hit, the ensnaring ivy effect is triggered for free.