This may be addressed in previous threads, but after browsing the forum for a while, I haven't found it.
Because suspending belief is a prerequisite for reading sci-fi/fantasy fiction, I try not to question any of the alien technologies or physical phenomena in the Animorphs universe. However, I've always wondered something, and I'm curious if anyone here has any theories. I'm on board with the explanation that, when morphing something small, one's excess mass is temporarily transferred to Z-space. I can even see that this may be part of the reason for the two-hour limit - perhaps after that much time, matter floating freely in the void will decay, and will be irretrievable. However, where does the extra mass come from when morphing something larger than oneself?