What's gonna be the next 50% chance for drop 5* gem ?

So this week its colossus engine. I have r4 20% and got 1 more copy today, not gonna upgrade because + few seconds for knock back doesn't look good for me.

Im curious what's the next gem will be? What if its roiling consequence? Its definitely OP gem that worth spending for bundles

What do you think? What would you like to see?