The new League of Legends champion, Samira, has been revealed on the PBE servers and she already has the unique ability to gift gold and do damage by using one of her emotes.
Riot already revealed that the new AD carry, Samira, is all about style. Her recent PBE addition revealed that she has the unique ability to do damage with one of her emotes and increase her style grade in the process.
Namely, her taunt animation gives one gold coin to the enemy and it does one true damage. This is the first time Riot decided to implement an animation that impacts the game with such consistency.
Her current state on the PBE servers allows her to use her taunt can apply certain on-hit effects like Landry's Torment or Scorch. Riot will surely balance and patch some of these interactions considering that some of these might be overpowered.
But there also might be a chance that by the time she hits the live servers, they give her the ability to apply all on-hit effects since it's a skill shot. This would mean that she could easily use aggressive sorcery keystones to poke the opponent with Arcane Comet or Sumon Aery which inflict bonus damage.
Another good use of the emote would be to proc the opponent's Bone Plating before engaging in an all-in. This could give Samira the upper edge in trying to finish off the enemy, especially in the laning phase when this rune has the biggest impact.
There are some similar interactions in the game but none of them are so common. For example, Zyra's character and plant models grow slightly larger if she gets hit by Leona's passive - Sunlight. If Maokai comes close to her, she gets one additional movement speed.
The famous "The Hunt is on!" event in which Kha'Zix and Rengar are tasked to kill each other is probably the most popular special interaction which proclaims the supreme predator between the two.