Ocean
not that super OP for champs like Heimer, since he is in combat a lot
but poke champs and teemo basicly get infinite mana from it
Redemption/warmog allow to counter Ocean drake
Teemo's w also gives movement speed incombat if no damage have been taken, witch allow him to compete with enemies that have cloud drake stacks
Morello flat mpen nice vs cannon mid/adc, but it eats away a item slot
it takes over 30sec to recall and cross river again
therefore a redemption prevents recalls and allow deeper shrooms