Epsilon, the Secret Weapon - character design
Just as a precursor: this is a design meant to split the original Zac from his new Q and R. There are people who love the old Zac kit--rightfully so, as the kit was fine and Zac was simply not in need of a rework. There are people who love Zac's new Q and R--also rightfully, as even Zac mains who want the original back will tell you that the new Q and R are great buttons. They were just never buttons meant for Zac. That was what Riot didn't seem to get, or want to acknowledge, about Zac's kit: he was never meant to stop moving. Aside from his E, his kit flowed, and even the E gave a distinct feel of a buildup before a flood. his kit was also always meant to incite chaos, which the new Q and R are the exact opposite of.
This idea presumes the following: -That Zac Q is reverted, in order to keep the new Q with the new R in a new champion. -That Zac's new lore is reverted to his old Superman-esque lore, which sure, wasn't original, but it's not like his new lore's something magical and never seen before either, so -That Zac is retitled from "the Secret Weapon" to "the Prototype" to free the designation for Epsilon.
Backstory, summed up: While unable to recapture Zac, his original creators were able to obtain a sample of his matter during their fight. Using this matter, they were able to recreate their designs, and with knowledge of the original's capabilities, were able to improve upon it, creating a new weapon, codenamed Epsilon.
Description: Epsilon is a large, amorphous creature with no discernible skin or organs. It seems to be entirely made up of a semitransparent gel wrapped around the upper half of a human skeleton. It oozes along the ground, using the skeleton within to give shape to its attacks.
Passive: Biotic Absorption -Every time Epsilon hits a minion, monster, or champion with one of its skills, it gains a charge of Biotic Absorption(max 1 per skill use, 2 for Grab and Smash if used on separate targets). When it reaches 8 stacks, it gains a heal over time that recovers [X]% of its maximum health. Killing a large jungle monster adds 2 charges of Biotic Absorption. -When Epsilon takes fatal damage, its gel falls away and exposes the skeleton beneath. The skeleton is able to move around, but cannot attack. If it survives [X] seconds, Epsilon will reconstitute itself at 50% health. This has a 300 second cooldown.
Q: Grab and Smash: On cast, send out a tendril in a target direction, dealing magic damage and slowing the first enemy hit, attaching for two seconds. While attached, Epsilon's next autoattack gains increased range and deals magic damage. If it attacks a different target, it will then lift and slam both targets together, dealing damage again in a small AoE.
W: Stab and Slam: Charge up an attack for up to 2.5 seconds, reducing movement speed during the cast. During this time, crowd control will affect Epsilon, but will not cancel the cast. If released early, Epsilon will stab straight in a targeted direction, doing magic damage and slowing the first target hit. If charged for at least 1 second, Epsilon will instead harden into a spiked ball, which will then slam down in the target direction, dealing AoE magic damage and knocking up any targets hit. While in the spiked ball shape, Epsilon takes reduced damage.
E: Search and Destroy: On cast, Epsilon launches its upper half in a targeted direction, dealing magic damage and attaching to the first enemy hit for 2 seconds. While attached, the target is grounded, and after 1 second, the ability can be recast. On recast, Epsilon will drag the enemy in its direction for a set distance, while hurling itself forward to land at the target's original position, dealing magic damage around itself on impact. Cooldown reduction will not reduce Search and Destroy's cooldown, but will increase its grab distance at a range of 10 units per 1% CDR.
R: Divide and Conquer: Epsilon spreads its mass over an area on the ground for up to 2.5 seconds, becoming unstoppable and slowing enemies in the area. If released early, Epsilon knocks all enemy champions within the affected area away from it and deals magic damage. If charged for at least 1 second, Epsilon instead scoops up all enemies on top of it and carries them toward the target location, dealing magic damage upon landing.
People who want old Zac can have him back, people who want the reworked parts can have those back, and everyone's happy.