Ok so i was playing jhin in urf 
. Then I got killed my talon, nothing much, suddenly a massive orange light comes down from the sky right where I died. This happens each time talon kills me. Then Kat kills me and a pink heart appears on top of me. I'm really confused as to what's happening.
It's a "Finisher" that is attached to 3 icons sold last URF.
That's kool that the icons you bought last year still work as finishers this year.
Alright, I will try to explain this better since the others just give you some overall blanket answer. Last year, Riot sold these 3 icons during URF. These icons will give you different death animation in the game mode. If you kill someone with the laser icon on, lasers will shoot them when they die. If you use the heart, you will get the nuclear heart explosion. If you use the ice, they will freeze into an iceberg before shatter.
I'm having a good time when the enemy has seen three giant hearts before minions spawn :D
I saw the pink heart too. I though it was some visual of the heartseeker's skins, but as you mention it - it is really time for a new champ :)
Ok so i was playing jhin in urf
there you go
