If a triggered ability of an Ally you control triggers, that ability triggers an additional time.

Trample

Whenever you cast a creature spell with mana value equal to Jackal's power, copy that spell, except the copy isn't legendary. Then put a +1/+1 counter on Jackal. (The copy becomes a token.)

Flying, first strike, trample, lifelink, haste

At the beginning of combat on your turn, other Spiders you control gain flying, first strike, trample, lifelink, and haste until end of turn.