The problem with changing the mechanic to adding is that it makes a lot more synergies, in mindgates, SoSers and Fractals, among others. Plus I don't feel like it thematically fits. If the community demands I can put up a poll to see the favoured option.
As for rewinding, wouldn't that technically makes this shrink? The idea a creature that would get bigger over time, and rewinding is turning back time... I'm not really sure (not to say it isn't a good suggestion).
Since people seem to be liking this idea, I'll work on finding/ making some art for it and getting it into voting.
Also, +1 Yay for the return of timetock