4th-D Slip is a PSI ability in Mother. It works on all characters, enabling them to warp out of any standard battle, excluding those against bosses. 4th-D Slip is realized in Mother by Ninten. It is recognized as a quite useful ability due to essentially being a 100% chance of an escape at the cost of PP.
- 4th-D Slip is likely related to time in some fashion -- time is generally regarded as a hypothetical fourth physical dimension (along with length, width, and height/depth), and it would certainly be plausible for Ninten to slow/halt the passage of time (or "slip" out of the fourth dimension) for an easy escape. The 4th-D Slip could also relate to a fourth spatial dimension, meaning Ninten would travel back and forth in the Fourth Dimension to avoid incoming attacks. Such methods would explain the 100% chance of escape.