Does attacker or blocker assign damage?

An attacking creature that is blocked assigns combat damage among the creatures that block it.

Can a creature with no power attack?

Yes, you can attack with a creature that has zero power. The effect only lasts for the attacking player’s turn.

Can you equip after declaring attackers?

The question is, will B now be able to equip the spear on his other creature before he declares attackers? You cannot respond to the declaration of attackers.

Can you tap a creature on your opponent’s turn?

Yep. If they have an ability that would do so, there is nothing stopping them (aside from Summoning Sickness, targeting, the usual). Unless you are playing with Area of Effect.

Can a untapping creature stop an attacker from attacking?

That’s true, untapping (or tapping) a creature after it has been declared as an attacker can never stop it from attacking. (Same goes for blocking.) But there are some cards that will say things like “Untap target attacking creature and remove it from combat,” which does stop the creature from attacking. – David Z Oct 14 ’13 at 11:27

What happens if you neither attack or block a creature?

Even if your opponent does not, you’ve traded damage, but you’re behind in the race. One way to think of things is that creatures provide value every turn that they attack or block. If you neither attack nor block with Wetland Sambar, then you’ve wasted a turn’s worth of its value.

What happens if you don’t put your creatures into combat?

The value of your creatures plummets if you’re unwilling to put them into combat. A classic example comes up when your opponent attacks a morph creature into your Archers’ Parapet. The morph could turn face up to be a 5-power creature, or the opponent could have a spell like Awaken the Bear in his or her hand.

Can You untap a creature in RuneScape?

While untapping does not stop an attacking creature, you can use an effect like Tumble Magnet in a player’s “Beginning of Combat” step to prevent a specific creature from being tapped to attack. It is important to note, however, that you must do this BEFORE your opponent taps their creatures to attack.