I think it would make sense in Life. Life is primarily about creatures, and, one could argue, growth, with mitosis and forest spirits. I think something like 'symbiosis' would be a good name, but I think someone already submitted a card with that name once, so I'm not sure if it's allowed to reuse a name. I don't see why not, but there might be a rule against it. I think it should probably cost a lot more than it does, though; it could potentially heal a lot of hp. It's similar to, but more situational than, Miracle, so it should be cheaper than miracle, but maybe not by a lot. Maybe something like 11 unupped and 8 upped cost, again going with the -3 reduction parallel with miracle.