i think this card is still slightly overpowered, but maybe i'm wrong, cant, but finger on it.
The best deck i came up with was this:
Deck would contain: mammoths, parallel universes, phase shields (to stay alive), lighting (to lower creature if necessary HP), Earthquakes (to stall opponent using his big units or built-up rush).
Reason: parallel universe will make the unfrozen copy. (since mammoth has a 'when enters' effect)
Practically this deck would be good against rushes, quanta stall and several rainbows.
But weak against Stall decks (depends stalling type), since no permanent destruction.
Time deck with reverses would just be annoying clean kill against you.
and bone wall would be just boooooring to hit.