The ant bug has long tentacles and a spiked midsection. I located it on my deck walking across the wood. (Somerset County NJ)
Coreidae or Reduviidae nymph
The photo I believe is of a Coreid nymph . These are the leaffooted bugs. The other possibility is an assassin bug family. With new tiny little nymphs it is hard to know for sure, but the antenna on yours makes me think it is a Coreid…would be great to see photos as it matures so we can positively ID it.
The Coreids are bugs that suck the juices of plants, but a few are reported to be predaceous.
Coreids often give off an unpleasant odor when handled. A few species of Coreidae are agricultural pests.
If it is an Assassin bug they feed on insect pests such as caterpillars, beetles, leafhoppers, aphids and such.