The computer has no eyes, so this means invisible to the player.
Theoretically this would simply be a change of the battlersprite to an invisible (fully transparent) sprite, but the states do not have any command function themselves.
So this means the only way to do this is by a plugin that adds that functionality to states.
Please specify and link to all other battleplugins you have in your project, because that info is needed to ensure compatibility.
I've moved this thread to Plugin Request. Please be sure to post your threads in the correct forum next time. Thank you.