Ah, i guess i should have actually explained it. If you spam the grab key repetitively while holding a movement key in the pool area and you go onto another capture area, the last frame of the tentacle remains visible until you hover over the spot again
here's a better video of it: https://www.dropbox.com/scl/fi/fwpl1co8uiqrg1ace9rf4/TL2-Short-Bug-Report-1.1-1....