The sticky splats as depicted on the PJ Masks website's Halloween costume contest advertisement.
Sticky splats are multicolored gooey blobs that Night Ninja and his Ninjalinos use to (temporarily) trap the PJ Masks during plots. It is unknown what they are made out of, but they are apparently strong enough to pin down a child, as they have successfully been used to pin down PJ Masks members. Oddly, as they are strong enough to keep them pinned down, the PJ Masks members can peel them off another member with ease.
In "Catboy and the Sticky Splat Slingshot", Night Ninja attempted to project large sticky splats across the city, but ultimately failed. In the same episodes, sticky splat webs were introduced. Sticky splat webs are similar to spider webs but are made of the same gooey matter.
In "Take to the Skies, Owlette", Night Ninja introduced splat grabbers, which are versions of sticky splats that can be extended to grab hold of something (in this case, the Owl-Glider).