Calling on the old ways

Whenever a Spirit Guide you control attaches to a permanent roll a 1d4. Results are are:
•1 You may discard a card then draw a card.
•2 You may put two +1/+1 counters on up to two target creatures.
•3 You may do three damage to a creature or planeswalker
{bull}4 You may sacrifice a swamp, if you do add {b}{b}{b}{b} to your mana pool. Until end of turn,
you don't lose this mana as steps and phases end.