Let's compare with Mutation.
That: 2 | 3. Unupgraded, it either mutates your creature, summons an Abomination, or destroys the creature. Upgraded, it summons a random creature with higher stats than the creature it was played on. (In my understanding.)
This: 5 | 4. Roughly 3 out of 4 turns it uses above card. Upgraded, it seems rather powerful as it would always increase in stats. I don't have much idea of the unupgraded other than 'it's Mutation on a stick.'
If someone else confirms this thought, I'd suggest increasing the upped cost or lowering the chance. Consider setting a fixed number of mutations or a 'once every X turns' mechanic.
