As a 'dipping toe into water' practice for the two paths concept, I've come up with 2 alternate upgrades for cards already in the game. I wanted the cost to be the same as the original upgraded version, and also the skills to be similar, so that it is obviously from the same unupgraded creature, as well as trying to make sure there would be no real bias towards one or the other upgraded version!
First one is an alternate upgrade for Forest Spirit:
The idea is that you've spent too much
on your Forest Spirit and turned it into an underwater plant/creature.
Still has the growth ability, but also defence against Fire, so good against Fireshield in particular.
Second is an alternate upgrade for Minor Vampire:
The idea came from reading somewhere that someone thought vampire should be bat-like in the game.
This card is weaker than actual Vampire, but has airborne skill.