Hi,
Thanks for your question. That's covered by this rule:
112.6k An ability whose cost or effect specifies that it moves the object it’s on out of a particular zone functions only in that zone, unless that ability’s trigger condition, or a previous part of that ability’s cost or effect, specifies that the object is put into that zone. The same is true if the effect of that ability creates a delayed triggered ability whose effect moves the object out of a particular zone.
Example: Reassembling Skeleton says “{1}{B}: Return Reassembling Skeleton from your graveyard to the battlefield tapped.” A player may activate this ability only if Reassembling Skeleton is in their graveyard.
Since Multani's ability says to move it out of the graveyard to your hand, the ability can only be activated if Multani is in the graveyard, not the battlefield or any other zone.
Thanks,
Nathan Long
Magic Rules NetRep