Sylas vs Sion

Weave an auto after each spell: Petricite Burst (passive) turns it into a chain swing around you, with bonus magic damage.

Save Kingslayer (W) to finish or to save yourself when your health drops: its healing grows with your missing health.

To engage, cast Abscond (E), then recast within 3.5 seconds: Abduct (E) pulls you to the first enemy hit and knocks them into the air.

Cast Hijack (R) on the enemy whose ult can turn a teamfight: you keep a copy of it, cast with your own stats.

Leave the area while he charges Decimating Smash (Q): past 1 second of charge, the hit applies a knock-up and a stun, for up to 2.25 seconds.

Break the Soul Furnace (W) shield before he detonates it: he can only trigger it if the shield still holds.

Step to the side of Unstoppable Onslaught (R): he turns poorly once it's launched, and his charge stops on the first champion hit.

Back off as soon as he dies: during Glory in Death (passive), his autos are much faster and deal damage based on your max health, but his health drains fast.