Board Game Arena

https://boardgamearena.com/gamereview?table=466537672 In move #188, I play a slow worm from display. The cost is 4, discounted by 3 (partner zoo), discounted by 3 (expert in small animals). So, it costs -2, but is displayed as 0. Display cost makes it cost 2 more, allowing me to play it. Is this int...