Very nice! A worthy champion for death.
One quibble I have is that it might be a little too expensive with the current stats, if we compare to other growth creatures in the game. Lava golem and forest spirit both use off-element costs and 1
![Rainbow :rainbow](https://elementscommunity.org/forum/Smileys/solosmileys/../../../images/Misc/rainbow18x18.png)
, while this is in-element and has the chance to add a poison stack as well, so the 'growth' can be modeled as a +3|+2. With an in-element growth the increased cost is justified somewhat, but then needing the creature to sacrifice slows this down by quite a bit even if we assume +3 (2ATK and 1 poison). Then again, I haven't really thought about the implications of auto-poison/infect on-death, so it may be fine as is.