Shadowverse

They couldn't or didn't want to exploit the system for a fleeting advantage.

Added 14 minutes later

It existed. It seems that despite Locken's complaints, this card might also work; it's easier for the dragon to upgrade one Olive, but the turtles can be used to move around the curve and avoid getting bricked. Although, I haven't played with a valet-dragon, maybe they don't brick as much.

2/4 trash without an ability is the last thing I'd want to play on turn four. At first glance, it might work with that 10-10 creature for 3 mana, but no more. And in general, evolution-dependent cards should see a doctor. Two expansions have been released after DE, and people on Twitch and Reddit are still freaking out about evolutions, stubbornly fixating on the essence of the cards in their minds as a one-dimensional gameplay mechanic.