Hello, I don't know if anyone already knew but I noticed some interrupt indicator to know when the behemoth is "unstable" and ready to be booped. I saw the same indicator on Embermane and Skarn (when he goes on two legs)
This indicator is some "orange exclamation marks" near the head of the behemoth. I think any behemoth ready to be booped have this indicator.
https://i.redd.it/h0lj6xgejou21.jpg