It's a powerful effect, for sure, and worthy of being on a Legendary, but I think it will prove too unreliable to see serious play
Together, the Starter Deck pair for Ursula's Return represent a nice balance for each kind of player, and look like a nice investment to get started with this new set
What's special about this version are borderless reprints illustrated by Greg and Tim Hildebrandt (two beloved artists in the fantasy genre) the borderless Poster cards on 20 mythic rare cards from the main set and the chase cards: double rainbow serialized cards from the Realms and Relics Box Topper selection, with just 100 copies of each
That's what happens when you combine Tinker (which could get out the Jar almost immediately) with Megrim (so that your opponent would take 14 damage from a single Jar discard, assuming they could not play any cards in time)
Whether its giving a character permanent buffs to health and attack or an ability that triggers when you do certain actions, the effects seem to be very strong