Living Seed becomes a spell, much like earth shield or beacon of light. Something along the lines of 'The healing done from critical effects will in addition be added to the living seed. After x amount of healing has been stored in the seed, the seed will burst providing the bearer of the seed to be instantly healed by x amount, along with x amount over time. In addition the bearer will be coated in bark like armor, taking on the appearance of a tree (similar to tree form) and reducing all incoming damage by x percent.'
This can only be cast on one target at a time, and put in a minor glyph that prevents a player from transforming if your friends are getting annoyed of looking like a tree