He does what Sans usually do, the ties of his boots are sometimes loose because of his laziness, he likes to toy with Echo!Frisk. He does smoke but only because he thinks it's "cool" he's also an alcoholic and he's drunk most of the times, he appears in Underpatch and Echotale at the same time and sometimes he's called G to shorten his name. Echo!Frisk and Gaster!Sans are a couple, he is also mysterious and his backstory is unknown. He has white eyes/pupils in his eyesockets. He calls you Kid