It's a fantasy role-playing game.

DM: You are Keyleth, a half-elf druid . You are the member of the famous group of adventurers. Previously, The other two spined devils run up and attack Vax, doing minimal damage. The bone devil catches up with the group and attacks Vax, but the rogue dodges every blow.
DM: Two twelves in a row. You just (whoosh), dodging out of the way, being crazy rogue, evading. That brings us now to Keyleth.
Player: Oh, shit. Can I change people as a bat?
DM: Yeah, as an action, you can change your form, which is an action.
Player: But can I stay as a bat and change other people?
DM: Yeah.
Player: Yeah?
DM: It says here, "On a subsequent action you can use your actions to transform affected creatures into new forms." So yeah. I don't see why you couldn't.
