Zoofights 1 - The end of the first round battle between Mechos the giant squid and a team of four cosmonaut gorillas. After taking huge damage from the gorillas' chaingun, a bloodied and battered Mechos finally silences the weapon, as well as three of the four gorillas. Grabbing one of Mechos' weapons, the final gorilla and Mechos engage in a tense Mexican Standoff... and they drop their weapons and embrace each other. "Enough souls had died this day."
Zoofights 3 - Odinkaru's death scene. The old, battle-weary bear dies a hero's death to Steamcrab, and awakes in Valhalla. "Open your eyes, my friend... Open your eyes!"
Zoofights 5 - The conclusion of the battle between Sega Gorillesis Mark II and Ro-Boto Cop, when Gorillesis puts his Mortal Kombat brain aside and instead makes a decision with his gentle gorilla heart to spare the crippled Boto. He swaps out his Mortal Kombat cartridge for one of Ecco the Dolphin, carries Ro-Boto Cop to medical attention, and later they share a few beers together at Gezora's bar before entering the Royal Rumble as a team.
Also from Zoofights 5 - the funeral held for Gezora is shockingly heartfelt, with a number of goofy roleplayers suddenly turning sober and writing or drawing tributes to him. Several people rewrote the lyrics of existing songs, the best one being a rewrite of Danny Boy. The user roleplaying as King TV Dinnah delivered a stream-of-consciousness speech about how he never thought he'd have to say goodbye that wouldn't be out of place when mourning the actual dead.
And of course, the Zoofights 5 finale. Despite being faced with a crisis of faith over his own existence, a world that only cared for his 'bote-building' whether he felt like it or not, and a nigh-omnipotent enemy, Croctopus leapt to challenge Gamma Constrictor, survived a collapse of time, and sacrificed himself to reboot the universe as a better place. Sail the stars, oh noble hybrid. You earned it.