This card first appeared in the first release of Hidden Dimensions and is also available in HD Spectrum and HD Xyth.
This is primarily a support ship. Taken alone, it is destroyed pretty easily without doing much damage to its opponent; but it can greatly influence battles in other lanes.
The best place to launch this ship would be in a lane that is already occupied by an enemy ship with a weak attack. Launching it in an empty lane will often draw attention from your opponent, making a counter-launch of some ship that will kill it fast.
After launch, you may consider using its ability to decrease the offense of its direct opponent to make sure it survives. After that is achieved (or, if you don't have enough time for it) use its ability to influence tight battles. For example, let's consider there's an other lane where two 5/20 ships are meeting, but your enemy has first shot. It will take him four turns to kill you, while you have three shots, leaving him a 5/5 ship. However, if you use Venom's ability here just once, it would take him five turns to kill you; and he doesn't get those because you'll kill him in four. He also gets four shots, but they still leave you a 5/4. And you've changed that result by just one ability use of the venom, early on in the battle.
Turns where you can't use its ability are rare, so keep in mind that it will cost you one energy every turn.