No sign of a spider web anywhere in the vicinity. Looked carefully for that too. There's no sign of any other activity ... even the tiny plants close to the ground didn't move when this plant was "dancing". Only other movement is the dried garlic leaf and the plant to the left that it hits as it flings itself back upright. Just checked again now the sun has gone down and the air is still. Standing perfectly still now. I'll check early in the morning.