Although a creature put onto the battlefield this way is attacking, it was never declared as an attacking creature
Whenever another cat you control attacks, you can pay one green, one white and one generic mana to give it trample and a +X/+X boost, where X is equal to its power
Manifesting cards lets you take the top cards of your deck and turns them into 2/2 facedown creatures, instantly letting you refill your board with tons of creatures when you get rid of one big one
Thallid Soothsayer Thallid Soothsayer is an excellent option if you're looking for a reliable card draw engine in your fungus deck
That, however, does not stop it being a pretty potent spell
Then you have a combat damage trigger which works with that evasion to draw two and discard two for card flow purposes unless you discard a Pirate, it's great outside of Pirate decks since looting for two is great in graveyard synergetic decks