Hearth Elemental

If an adventurer card ends up in exile for any other reason than by exiling itself while resolving, it won’t give you permission to cast it as a permanent spell.

An adventurer card is a permanent card in every zone except the stack, as well as while on the stack if not cast as an Adventure. Ignore its alternative characteristics in those cases. For example, while it’s in your graveyard, Questing Druid is a green creature card whose mana value is 2. It can’t be the target of Tenacious Tomeseeker’s triggered ability (“return target instant or sorcery card from your graveyard to your hand”).

If an effect copies an Adventure spell, that copy is exiled as it resolves. It ceases to exist as a state-based action; it’s not possible to cast the copy as a permanent.