Why "frogs"?

[Lulav]

three unclean spirits like frogs come out of the mouth of the dragon, and out of the mouth of the beast, and out of the mouth of the false prophet.

There is the dragon
There is the Beast
There is the False Prophet

Each of these has an unclean spirit

Like a frog.........................

In the NT there are various unclean spirits spoken of but I searched the Tenahk and found one place in Zachariah

An End to Idolatry
1"In that day a fountain will be opened for the house of David and for the inhabitants of Jerusalem, for sin and for impurity. 2"It will come about in that day," declares the L-RD of hosts, "that I will cut off the names of the idols from the land, and they will no longer be remembered; and I will also remove the prophets and the unclean spirit from the land.

It seems that both here in Zachariah and in Revelation we are speaking of an unclean spirit to do with Idolatry.

These three seems to be promoting it while looking to be of G-d.

The next verse tells what they are:

For they are the spirits of devils, working miracles, [which] go forth unto the kings of the earth and of the whole world, to gather them to the battle of that great day of God Almighty.

Some say the Dragon Represents Pagan religions starting at Babel and the Beast represents the False universal religion and the False Prophet is representing her daughters.

Praying to the dead, 'speaking in tongue's, "Christian yoga" Eastern 'arts', all these things and more like them open up the way to evil spirits to enter in and deceive G-ds people.