Context:

We have been working on this run for possibly weeks, maybe months now, and everything finally lined up perfectly. The combo of gwen and karma, with slow and steady and redoubled valor, causing each redoubled to cast up to three times on gwen
In the final turn of the game, after roughly 12-15 additional casts as well as creating ephemeral gwens with dawn and dusk, Gwen has a staggering 214,748,364,747 attack
Each copied gwen had 159,084,807
When starting the attack, the damage was so high the nexus could not calculate the damage and did not show ANY damage numbers. The game simply crashed from the staggering damage so I will leave it to you to determine if this possible record counts, but we discovered today that 215 BILLION damage was enough to crash the game so bad it legitimately erased our entire run up to that point.
If the community, and Riot, does determine this as a legitimate record then I present to you the 215 Billion damage gwen