I don't like the halving idea. It is entropy so the stats should be random but sum to the original creatures.
No I like it how it is, it's a weak Twin Universe that halves both creatures' stats. However, how do you deal with 1|1 creatures?
Possibly outcomes for a 1|1 are:
1|1 and 0|0 creatures
1|0 and 0|1 creatures
Though you make a good point, because if this was how it always operated, it might suck to cast it on say a 12|12 dragon and come up with a 12|0 dragon and a 0|12 dragon. That said it might be nice that there is a negative risk since it is cheap and an entropy card...
Pretty low risk though as the larger the creature's hp the less likely it would result in a N|0 creature...
Two new creatures would be formed, none of the skills would remain. However their stats would be based on the original creatures current stats, not max stats or initial stats.
The main unanswered question is what Creatures should result.
Random? Mutant? Abomination? original creature?