This happened today. The enemy team finished killing rift herald but my team chased them off and killed most of them before they could pick it up. The enemy Illaoi was alive and had teleport, so I used sweeper around the pit to prevent her from TPing in and picking it up. Then I saw that the rift icon thing actually has three hit points, just like a yellow trinket, and I killed it, while everyone else in the game was typing “???” “Wtf” “I didn’t know you could do that”.
So that’s what I learned today. Rift herald is coded like a trinket ward. This happened in a mid-diamond game and none of us knew, so I’m assuming it’s very uncommon knowledge.
Edit: realized it’s called the “eye of the herald”