In music notation, a sixty-fourth rest is a pause in the music lasting for one-sixteenth of a beat, the same duration as a sixty-fourth note. It is drawn as a thirty-second rest with a fourth flag in the middle of the staff.
On the staff, a sixty-fourth rest looks something like this:
/\
---| /-----------------------------------------------------
|/ *-/
---/------------------*-/----------------------------------
/| *-/
-/-|/\--------------*-/------------------------------------
| | | /
|--|--|-------------/--------------------------------------
\ | |
--\|_/-----------------------------------------------------
|
\|