The X-Men credits are unfortunately incomplete (after Season 1, the end credits would only list the lead voice), so sources differ on when the recasting took place. However, to my ear, Kolikos voiced the Apocalypse in four episodes: "The Cure" and "Come The Apocalypse" in Season 1, and the two-parter "Time Fugitives" in Season 2. Even with his limited time, Kolikos had to deliver a few memorable lines:

"I know more about this world than you ever dreamed! So I must destroy it!"

"The old world is passing. Together, we will create a new one in fire and blood! From the ashes of this world, I will build a better one!"

"Come forth my Horsemen, and let Chaos cleanse the world!"

My personal favorite is in "Runaways in Time," when a man looks at Apocalypse in fear and shouts, “Mutant!” A steely-eyed Apocalypse sneers and declares, “I'm as far from mutants as they are from you!”

When "X-Men" premiered, Apocalypse had debuted in the comics just six years prior; Louise Simonson and Jackson Guice created him in 1986 as a villain for their X-Factor comic. Apparently, Apocalypse's first appearance on the X-Men adapted the only thing he was known for at the time: turning the X-Men character Angel into one of his four horsemen, complete with new steel wings.

As the first actor to ever play Apocalypse when the character was still young, Kolikos' voice set the standard—for Blendick, of course, but also for future Apocalypse actors like David Kaye and Oscar Isaac. That voice became a key part of why young X-Men fans (and even some future X-Men writers) remembered Apocalypse, with his dominance of the animated series securing a continuing A-list role in the comics.

Apocalypse's real name, En Sabah Nur, supposedly means "the first" in Marvel Comics. (In reality, the three words are Arabic for "Seven Lights," i.e. dawn.) Just as Apocalypse marked the dawn of the mutant race, every future Apocalypse actor relies on the exemplary work of John Kolikos as they keep the character in life.