Idk, seems needlessly convoluted and complex to me.
I think a pack should return to deck as a piranha when played. Also, I think you should change n to equal maximum attack +1, or increase the piranha costs by 1 (2
, 3
) and give them the starting stats of 1|1 and 1|3. Although I assume you could use unupped piranhas and nibble the other one get one with 1 attack...meh. Also, I think you should change the pack trigger to 3, because 5 is just asking for fractals, and that means that that mechanic is exclusive to aether-water duo.
Of course, this could be all part of your master plan to introduce such a complex monster that's so situational. I really don't even know if it's that situational or not..