Okay, I'll admit it, Gangplank (the pirate) and Alistar (the bull) are unlikely lane partners. Some might point out that it's probably staged (look how Gangplank stumbles drunkenly instead of running away). And it's not exactly professional-level play. So why, just last week, was it the most popular YouTube clip within a community of five million daily players? Survivorship bias be damned, let me tell you what makes this clip so great.
1) To the unitiated it's pure slapstick, a sight gag that almost anyone can appreciate. If you don't know how League of Legends works in general, or how the typical bottom lane operates more specifically, it just looks like an anthropomorphic bull ran right into sniper fire. The action is hectic but human-readable. A taste like this might be enough to start someone from the general public down their fandom career path to Garry Crawford's category of the "Interested" (2003, 228-230).
2) While this clip's concept and editing are derivative of another League gag video, it couples character design to the comical audio mixing of Dion's "My Heart Will Go On." Essentially, a pirate-themed character escapes an enemy who summons tidal waves while losing his partner (an acute match for Titanic's ending). It also fits into wider memes about Gangplank, who is generally considered to be ridiculous.
3) With insider knowledge, this clip becomes the epitome of League's most contentious player dynamic: the relationship between a support and her carry. Briefly, Alistar (the bull) is a support character whose job in lane is to protect a "carry"—in this case, the pirate Gangplank. A support spends her pitiful income on vision wards that cut space out of the fog of war, and she never takes potential gold from her partner. This is because the carry is weak in the early game, but incredibly strong in the late game. This unique role assignment serves as a convenient bridge between eSports appreciation and fandom for American football (carries are like quarterbacks).
At the extreme of the support's responsibilities is this: If the carry might die, a support should attempt self-sacrifice. In the clip, Alistar executes split-second timing to cast a Flash spell into the sniper's bullet. It's a shining moment for the support, who rarely gets a chance to make big plays. And to those in the know, it's as touching as it is hilarious.