After being suitably impressed by the prehistoric lure Mel (as Paul) is being allowed to open a bottle of that closely guarded fishing secret, "The Light of AAPGAI".
The recoil can cause whiplash and the cap to fall off, hence the second hat. Sunglasses are mandatory with this stuff and it's lethal to the uninitiated. Mel's getting excited though as some fishing will be done in the next picture (and maybe some time travel!).