To those who think unmounted kled is useless

http://leagueoflegends.wikia.com/wiki/Zac

Upon taking fatal damage, Zac splits into 4 uncontrollable bloblets that move to his final location over 8 / 7 / 6 / 5 / 4 seconds. If any of these bloblets remain at the end of the duration, Zac recombines and returns at 10 - 50% maximum health, based on his bloblets' total remaining health.

http://leagueoflegends.wikia.com/wiki/Kled

[When dismounting] Kled['s] ... base movement speed is reduced「 by 60 」and his basic attacks deal 80% AD. ... Returning to the base fully restores Skaarl's Courage and health. ...

( '...' stuff is omitted because it's useless fluff in nearly all contexts )

Kled's passive should be viewed as a different take on Zac's passive, and stronger version of it, too. In either case, most of the time, they'll just kill you again to secure your death and there's little you can do about it by yourself. However, both will allow you to sometimes deny an opponent their rightful kill depending on the circumstances, and both can be used to tower dive with minimal risk, because the tower will retarget to minions in Kled's case (if the dive is done correctly; ie he kills before being dismounted and there are minions left under tower) and the blobs that are out of range with break turret aggro and the turret will retarget to minions. (Same thing, Zac has to kill before his passive activates, and there have to be minions left, I don't play Zac, so position of the blobs and Zac's main body when they fall might matter.) The difference is Zac regains full mobility after the blobs recombine while Kled has to make the entire escape with gimped mobility and that Zac has to wait five minutes, while Kled will have it when he bases next, allowing him to tower dive consecutively.