Kalista Rend Brainstorming
When Kalista kills a enemy champion with Rend 25% of the damage from the executing rend spreads shards of spears to nearby allied units (this effect would be called Shrapnel)
I'm not a math expert, but let's try some math to help picture what the damage would be like:
Kalista has 230 AD (60% of this is 138)
60 + 138 = 198 198 per stack x 15 stacks = 2970 damage rend 25% of 2970 = 742.5
742.5 to each nearby player assuming you rend in the theoretical range of them.
I thought about this when I realized the state of Kalista and how she compares to the new champion Xayah, a champion who can fly into invulnerability AND shoot stacks over (in a fortunate situation) an entire team, not only bursting them, but also rooting them. I'm praising Xayah for her ability to be so impactful as an ADC, but my favorite marksman; Kalista, does not have such impact from a similar style of gameplay (stacks and invulnerability ult).
Remember that the developers of Kalista did intend for her Q to be able to spread stacks to nearby enemy units, which is a similar effect to the Shrapnel effect, but the likeliness and availability of this happening is very rare unlike the Shrapnel effect. (This is coming from someone who killed a lategame Twisted Fate by stacking a superminion then Q + E on him in 1900 MMR)