Good attack and might be able to trigger some of Death's cards after a few turns.
Unbuffed, it can deal 14 and 18 damage respectively within three turns. The closest unbuffed damage a 2
creature (Horned Frog and Giant Frog) can do within 3 turns are 9 and 15 respectively.
My only concern is that Death employs fast and permanent hitters such as the Flesh Recluse and the Elite Mummy so this card might be overshadowed. Perhaps an extra 1 or 2 HP would make it a bit more attractive to use.
BTW, I wonder what this guy would look like when hit by Rewind.
I've been rolling around stat balance for a while now. I could add a couple more hitpoints, but I dont want its overall stats getting too high.
Mainly because of chimera abuse...
Transfering shamble will help, but I don't want them supplying too many hp at the same time...
I guess 1 to 2 more may not hurt though.
The other reason is that they are actually supposed to die fairly fast. This lets them get use for death effect fodder as you noted earlier...
Hmm... What if I beef up the hp but also bump the starting poison count? This would make them useful as catapult fodder as well

Updated version posted.
Moved stats to 7|5 and 2 starting poison unupped and 9|8 with 3 starting poison upped
So it still attacks 2 times over 3 rounds then dies, and deals the same damage but is slightly more resistant to CC and makes a nice choice of catapult fodder.
(4

for 5 damage and 2 poison unupped or 3

for 7 damage and 3 poison upped.)