can i tribute my opponents monsters with its effect?

here is the text and netrep rulings

Text
If you Tribute Summon this monster by Tributing 3 monsters on the field, destroy all Spell and Trap Cards on your opponent's side of the field.

Rulings
You can Summon "Moisture Creature" by Tributing 2 monsters, but the effect will not be activated.

You cannot Summon "Moisture Creature" by Tributing 3 monsters if there are no Spell or Trap Cards on your opponent's side of the field.

If you activate the effect of "Moisture Creature" and your opponent chains "Book of Moon" to the effect, the effect still resolves and all Spell and Trap Cards on your opponent's side of the field are destroyed.

No you cannot, you must tribute your own monsters.

The only way you can EVER tribute your opponent's monster (without taking control of them) is with a card effect that specifically states you can.

Lava Golem and Soul Exchange are the only one's right now that allow you to do such things.

But Soul Exchange is the only one that will work toward Moisture Creature or Gilford the Lightning's effect (you still need to steal two more monsters from your opponent or tribute two of your own).

Or just one of your own if that 1 happens to be Kaiser Seahorse, lol.