There are two ways to SPARE Muffet.

Option 1: Spider Bake Sale

If you buy an item from either of the two Spider Bake sales (Spider Donut or the Spider Cider) and use it in battle, Muffet can be SPAREd instantly without having to fight her.

There are two Bake Sales in the game. The first can be found in the Ruins and is the cheaper of the two, with the Donut only costing 7G and the Cider 18G. In the CORE, both will cost 9999G.

Option 2: Wait her out.

If you have to SPARE Muffet manually (because you couldn't afford the Donut or the Cider), you need to wait long enough (17 turns) until Muffet receives a telegram from the spiders in the Ruins who will explain that you are not evil to spiders.

Here are some pointers for the Muffet fight if you need to wait her out.

• Muffet's first attack is to turn your heart purple. Don't pay her anything. It is a waste of cash at this turn.
• The trick in this fight is to look at the sign that is held up while it's your turn. It will either show a spider, two spiders, a Donut or a Croissant (boomerang).
  • If the sign is a spider, she will send a pattern based style attack at you. Two spiders means that the amount of spiders will be larger.
  • If the sign is a Donut, she will throw Donuts at you instead. The Donuts do not follow the lines of the web and bounce around the box.
  • If the sign is a Croissant, she will throw Croissants at you. The croissants will make to about a third of the battle box and then return the same path.
• By far Muffet's most dangerous attack is her summoning her 'pet'. This will occur three times during the battle. First the battle box will begin to move to the left, whilst spiders come across in the shape of a pattern. After that her 'pet' will appear on the bottom of the screen and will begin to consume the web. Keep moving upwards, all the while dodging spiders.
• Paying Muffet halves her damage for one turn. The price increases with each turn paid.
• Struggling three times makes Muffet halves the price to pay her. This can only be done once and the effect only lasts one turn.

The problem is that the more monsters you kill, the less frequent the random encounters are. This can make the last couple very tedious. However, there is a cool hack/trick that I have found to help you get the last one.

1. Go to an area that monsters definitely can spawn in. They usually don't spawn in puzzle rooms, so just go somewhere that you remember having a random encounter in.

2. If you are in fullscreen, hit F4 to go back to windowed mode.

3. Hold down an arrow key. Any arrow key, doesn't really matter, but don't walk into a wall or an object.

4. While you are still holding down the arrow key, press alt-tab. This will cause the game to lose focus. However, Frisk will continue to walk without actually moving. The game registers this as you walking.

5. Watch youtube until a random encounter happens. This shouldn't take more than 2-3 minutes at most.

This doesn't make grinding very much faster, but it definitely makes it less tedious.