I want to pretend I’m the grung goddess Nangnang, and I thought of using Disguise Self to make that illusion. My party will support me with Daylight, Minor Illusion, yelling Grung phrases into a horn that amplifies and distorts them, Fog Cloud and a Griffon for a stylish landing, and an invisible Imp touching the Grung King as I pretend to touch him from a distance (to avoid physical inspection).
Disguise Self states that
You make yourself look different until the spell ends. You can seem 1 foot shorter or taller and can appear thin, fat, or in between. You can’t change your body type, so you must adopt a form that has the same basic arrangement of limbs. Otherwise, the extent of the illusion is up to you.
Now, Grungs are fairly different from regular humans, but they are still humanoid, have similar limbs, etc. I would become a very big Grung, but that is to be expected, I’m a damn Goddess! Is this plan feasible?