Cast this spell only during your turn and only during combat.
Choose one —
• Creatures you control gain double strike until end of turn.
• Untap all creatures you control. After this phase, there is an additional combat phase.
Entwine {1}{R} (Choose both if you pay the entwine cost.)
The additional combat phase is directly after the combat phase in which Savage Beating is cast. There isn’t a main phase between the two combat phases.