It sounds like you’re referring to a “WET” PKG file for PS3 — likely the game WET (developed by Artificial Mind and Movement, published by Bethesda, 2009).
Notes:
Dynamic XMB Mods: It can also refer to PKG installers that add dynamic water effects or "liquid" textures to the PS3 background, giving the aging console a more modern, high-definition appearance. How to Install PKG Files on PS3 wet ps3 pkg
Appendix B – Tools to Analyze Wet PKG