Goop controls his slime with his Anti-Gravity Projector, if Goop and the Anti-Gravity Projector are separated by at least two feet, Goop's body will become inert until the Anti-Gravity Projector recollects it.
Goop's Anti-Gravity Projector allows Goop to take any shape and fly.
Goop can manipulate his Anti-Gravity Projector to fly away and cut enemies.
If Goop loses his Anti-Gravity Projector when going through an obstacle, the Omnitrix/Ultimatrix can create a new one instantly.
Goop is able to fire slime with acidic or sticky properties upon impact.
Goop is limited to his Anti-Gravity Projector controlling his body. If it is separated by two feet, more or turned off, Goop's body goes completely inert.
It is shown that Goop can be hurt by being spun really fast.
Because of his slime body, the Omnitrix/Ultimatrix can be easily pulled off and reverting Goop to normal and removing the Omnitrix/Ultimatrix from the user. This weakness is elliminated when the omnitrix is on the anti gravity device seen in Ben 10: Omniverse.
According to Dwayne, Goop is a single celled organism.
Goop is the first alien that Vilgax ever transforms into.
Goop's Anti-Gravity Projector isn't part of Polymorph biology, this is due to the difference of gravity between Viscosia and Earth. If Ben was on Viscosia, or another planet with similar gravity and turned into Goop, it is unknown if Goop would still have the Anti-Gravity Projector.
Goop was the first of Ben's alien forms whose name comprised of only a single syllable.
Goop's Anti Gravity Projector became a substitute for the missing Anti-Gravity Multiplier on the planet Pisciss