The Drooling Dude starts off with 14 attack and 11 defense, making it a fairly weak Algebraic Rare card in comparison to stats. It is, however, a Rainbow card, so it can be placed anywhere and will not interfere with any strategy. It is probably better to position it on a far-end landscape, as its Floop does not affect adjacent creatures.
The Drooling Dude's Floop ability costs 2 magic points. When activated, the Drooling dude will gain +7 attack and +3 defense. This will quickly become a very valuable card, as within a few rounds it can go up to 35 attack. However, you should use it in conjunction with a building that increases its defense, such as a School House, which will make it immune to Cerebral Bloodstorm after four floops.
He's pretty easy to craft so you should try to craft him as fast as possible.