I think that
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fits. Maybe
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could fit also, since it deals with spreading things away, somehow.
On the card: the unupped costs too much, imho. Make it costs 2
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, it's balanced by its low stats anyway.
Upped seems fine to me.
EDIT: on the technical side, i suppose those starfishes would be implementes considering current stats and maximum stats.
So, when you split a 4|4 you get two 2|2 that have 4|4 as maximum stats. Basically, this creatures regenerate 1 ATK and 1 HP per turn.
This also means that if (for example) a starfish attacks a fireshield, it would takes 1 damage and regenerate it the next turn.
I don't know if there are other way to implement this, but i think it's fitting, since the ability to divide comes from a great regeneration ability.