Myself is a pronoun. Famous users of myself include Billy Idol, De La Soul and prominent Australian masturbation-enthusiasts DiVinyl.
Example: "I myself will challenge the winner!"
Context: Pool. Magic cards. Halo 3. A fight to the death in gladiatorial combat (what I myself like to call Thursday)
Meaning: I'm so fucking bad-ass that whoever wins between you two bumblefucks will earn the right to be beaten into faggotry by me, myself.
Example: "I gave myself a good once over."
Meaning: I'm constantly diddling myself due to boredom, lack of social ability and the fact I've been set about with a fugly bat on several separate occasions.
Never heard of 'the changeup'
Example: "My wife and myself fully agree"
Context: Any question directed at you and your significant other.
Meaning: My wife wears the trousers and is always right. I am a pussy-whipped spineless shadow of a man. I never disagree with a word she says.
Just keep tellling yourself you're in charge.
Example: "I'm not feeling great, but I'll be back to myself soon"
Context: Trying to explain why you look/feel/act less than awesome.
Meaning: Trying to imply that your usual self is so much more stupendously awesome than you could ever be, and that on the right day, even superman would be begging to blow you.
God just shit his pants.
This image will never leave you.