@tennoseremel easy! It even says right in the documentation for zap-up-to-char:

>

> Kill up to, but not including ARGth occurrence of CHAR.

> When run interactively, the argument INTERACTIVE is non-nil.

> Case is ignored if ‘case-fold-search’ is non-nil in the current buffer.

> Goes backward if ARG is negative; error if CHAR not found.

> Ignores CHAR at point.

> If called interactively, do a case sensitive search if CHAR

> is an upper-case character.

To set a negative argument: C-u - M-z ("Control-U minus Alt-Z")

Just as a reminder, to lookup the documentation on functions and commands: C-h f zap-up-to-char<RET>

Also, just FYI, you can set the mark highlighting and run interactive search C-s or C-r and the search will not cancel the highlight, so you can highlight up to a search string.