I'd say the unupped creature needs at least 15 to be useful. That would also fall in line with how most upgrades work; they provide a small improvement or change. Not make it thrice as good.
You'll need to spell Gravity pull with a capital letter, and Freeze = 3 turns, Congeal = 4 turns. No need to specify how long they're frozen/congealed. Thus, I suggest the following wording: "Creatures that deal damage to this card are frozen. Gravity pull."
Replace "frozen" with "congealed" for the upped card. Now, I know the spell Congeal specifies how long a creature is frozen, but it also calls it just that; frozen. Squid doesn't. I think it's a good thing to have separate terms for them. Consistent, and encourages the individual player to do research.