Schizophrenic 'AT'

Once upon a time there was AT

Who combined with B to make BAT

But B ran away and C came to play and thus AT became CAT

C had an appointment to make, so F jumped into his place. So AT was FAT.

But F had a date with E.

(So ran away did he)

And H took his place. Now AT had a HAT

But T joined the party and thus HAT was THAT.

T and H decided to go to a ball and M joined to AT and AT became a MAT

Then G and N took over M's place and MAT became Pesky the GNAT.

Then G and N were replaced by P and all AT got was a PAT.

PAT came upon R and was dismayed to find that when AT joined R,

She was scared by a RAT

But S took over R's place and the RAT was been SAT

UPON! And SAT found V and S went into a VAT.

And when V ran away, that was all for AT.