Insect and Spider Identification: CLOSED: What are these odd things on my Elderberry tree?, 1 by WUVIE

WUVIE wrote:
These worms remind me of the little character worm on
the movie "A Bug's Life".

Hubby was just walking around spraying things when
he noticed not one, but five of these things clinging to,
or munching on, our Elderberry tree.

Could anyone identify these things? I moved one with
a leaf, then it responded by getting my thumb wet. My
son had to aggitate by saying it sprayed venom on me.

(eeeek!)

Many thanks for any ideas you may have.