I really like the idea but i think it's actually too weak to be useful VS the average deck.
First of all, 4 turns is rediculously long. Make it 2 at most.
His quanta cost is still quite high compared to stats, relative to his negative ability.
A good example is Arctic Dragon.
13/5 for 11 quanta. Bear is 10/6 for 7 quanta.
-3 attack +1 health -4 quanta. Without the ability, that's only slightly better than the dragon. With the ability, it's considerabley worse.
Or compare it to gargoyle. 7/3 for 5 quanta. With a postive ability.
+3 attack +3 health +2 quanta. Negative ability vs useful one.
Best example, come to think of it, is elite shrieker.
10/4 for 8 quanta.
+2 health -1 quanta. Really good ability vs negative one.
Mother grizzly makes me think that the ability should be something like 'Grow +2/+2 for every creature placed' with much lower initial cost and stats, this would fit the growth and life feature very well, as well as having good synergy with life's cheaper creatures. It would be the opposite of death's vulture. But that's just another card for another day (Feel free to take the idea, i'm too lazy to create the card.)