The longer answer is yes, it's technically possible, but you shouldn't.
DNS servers put additional records in what's called (unsurprisingly) the "additional" section of the response.
Strictly speaking, though, according to RFC 1034, the additional section "carries RRs which may be helpful in using the RRs in the other sections". For example, if you ask for the NS records for a domain, the A records belonging to those name servers might come along for the ride.
However if you try to supply unrelated data your DNS clients and caches will generally throw it away. RFC 2181 gives a priority table showing how "trustworthy" DNS clients should treat different sorts of data. Specifically it also says:
Unauthenticated RRs received and cached from the least trustworthy of
those groupings, that is data from the additional data section, and
data from the authority section of a non-authoritative answer, should
not be cached in such a way that they would ever be returned as
answers to a received query. They may be returned as additional
information where appropriate. Ignoring this would allow the
trustworthiness of relatively untrustworthy data to be increased
without cause or excuse.
i.e., data you put in the additional section can never be promoted into real answers.