C'thun appearing in game replay after playing Crystal Core

[beheh]

@tiagott-hs commented on Mon Sep 24 2018

While viewing a replay from one of his games, a customer reported that a random C'thun showed up on the battlefield right after he played Crystal Core. I checked other games and confirmed this seems to be happening pretty consistently. Not sure if only for discounted Crystal Cores or not.

Replay examples:
https://hsreplay.net/replay/e224AavinHyJsY9uB4nGfR#turn=10b
https://hsreplay.net/replay/KUWeaCFTfGpWDv4J7tzhh8#turn=7b