"A disc of leaf with luminous veins."
"The top of the glowpad shimmers like the heat of a distant desert horizon."
Glowpads are only found in salty water. They are immobile, but will attack and kill any Glowfish, if they swim too close to them.
Glowpads are quite tough, even compared to higher level creatures. Though not particularly threatening to even a moderately armored character, a character still using their starting weapon may wish to find something more productive to do than wailing away at this living punching bag.