Copycat

To put it simply, Copycats copy the magic around them. They can mimic forms, too. 

Minor Shapeshifting

As an action or a bonus action, you may change any part of your body deemed minor by your DM, such as eye color, pupil shape, hair color, etc. It may be just enough to make you unrecognizable, if you're lucky...

Additionally, these spells are added to your Sorcerer spell list;

Spell Level	Spells
1st	Disguise Self. Cause Fear
2nd	Alter Self
4th	Polymorph
5th	Seeming
9th	True Polymorph, Shapechange

 

Minor Mimicry

When you witness a spell you don't know how to cast be cast, you may spend a sorcery point per level of the spell to learn it until dawn of the next day. Cantrips cost 1 sorcery point, as do first level spells. You will need to supply material components, if any. You cannot copy a spell you already know, and class restrictions on spells are nothing, as long as you have the spell slots for it, you can cast it after its copied. 

Advanced Mimicry

When a spell is copied, you may use your reaction to cast the same spell, centered on it's original caster. Casting time is unaffected here, the spell will be cast in a reaction. This costs you sorcery points and spell slots needed to copy and cast the spell.

Advanced Shapeshifting

You may spend an action to shapeshift. This includes giving yourself natural weapons, giving yourself a climbing/swimming/flying speed of 30 feet, darkvision etc. Use normal stat blocks for natural weapons, and get creative.

Perfect Mimicry

You can perfectly copy a person's appearance, down to clothing, speech, mannerisms, and even magical abilities. The longer you spend in their body, the more of their memories become yours. Eventually, you may be unable to tell the difference... You can still cast your normal Sorcerer spells in their body. Upon leaving their body, you may use their magical abilities, whatever they may be, for up to 1d4 weeks.