comic vs signora epic rap battle

Almost all of Sans's attacks use KARMA (KR). This effect applies (to use terms of a general RPG) a "poison" effect to the attack: getting hit for even one frame inflicts not just the one damage, but also increases KARMA by some amount (depending on the attack). Whenever KARMA is above zero, it eventually drains back down to zero in increments of one, inflicting one damage with each drain. Because neither flavor text nor Sans explain KARMA in-game, it is unclear if it is linked to the lack of invulnerability during the fight which allows attacks to hit up to thirty times per second.

For example, getting hit by a certain attack for one frame inflicts one damage but may also increase KARMA by five. This means that even if the protagonist does not get hit by any more attacks, even while the menu is open, they slowly take one damage five more times, for a total of six damage (after which KARMA goes back down to zero). Getting hit by multiple attacks causes the KARMA increases to stack up, so if the protagonist gets hit by another attack, their KARMA may increase by five again (even if it has not finished draining yet), causing the protagonist to take one damage another six times.

While KARMA is above zero, it appears as a pink-purple health bar overlapping the usual yellow health bar, and also causes the protagonist's HP to be displayed in pink-purple text instead of white.

KARMA cannot exceed 40 and also cannot cause the protagonist's HP to fall below one. The more KARMA damage is built up, the faster it drains.

Technical Mechanics

Sans's various attacks increase KARMA by different amounts:[2]

Bone vertical loop: 5
Gaster Blaster: 10
Single menu bone (top left): 2
Four menu bones (bottom): 1
Other: 6
For KARMA to stack up linearly, the protagonist must be hit by separate attacks (e.g. three Gaster Blaster hits for one frame each increases KARMA by 30, dealing an eventual total of 33 damage). If the protagonist stays in a single attack, KARMA only increases by one per frame (e.g. one Gaster Blaster hit for three frames increases KARMA by 12, dealing an eventual total of 15 damage).

KARMA takes one frame to drain if maxed out at 40, two frames to drain if between 30 and 39, five frames to drain if between 20 and 29, fifteen frames (or half a second) to drain if between 10 and 19, and thirty frames (or one second) to drain if between 1 and 9. This means that KARMA when maxed out drains halfway within 66 frames (2.2 seconds) and completely within 491 frames (~16.4 seconds).

The items that increase INV, the Torn Notebook and Cloudy Glasses, grant small fractions of INV during the Sans battle. Specifically, the Torn Notebook increases INV by 1/5, the Cloudy Glasses increase INV by 1/4, and both items together increase INV by 1/3. This means that with both items together, the protagonist obtains a single frame of INV every three frames, causing Sans's attacks to hit up to 23 times per second instead of 30.[3] The two items also slow down the rate at which KARMA drains, increasing the frame delays to 2, 4, 8, 20, and 40 respectively when equipped together. This means that KARMA when maxed out drains halfway within 114 frames (3.8 seconds) and completely within 682 frames (~22.7 seconds).

It was intended that equipping only the Torn Notebook would give a 1 in 2 chance that KARMA drain is slowed down, and that equipping only the Cloudy Glasses would give a 2 in 3 chance, but due to a bug in the code, there is barely any slowdown when one of the two items is equipped. Equipping both items together behaves correctly.