We use tacky glue because it dries quickly.
Since he likes to take things apart, he also has a collection of wires and pieces of electronics. He found just the right thing to add to his robot.
This one below was a gift for one of his grandmothers a few years ago. I helped him add embroidery thread for attaching the arms. He glued glass beads for buttons.
And here is the grass reindeer we made a few weeks ago. Have you made one yet?