BYSSEPS ("Biceps") is one of the Glyphs you can find in a game of Desktop Dungeons. When used, this Glyph gives you a normal +30% Attack Bonus for one melee attack. This Glyph may spawn randomly in any dungeon and does not need to be unlocked.
BYSSEPS is cast by simply clicking it.
When cast, BYSSEPS gives a +30% Attack Strength Bonus for your next Melee attack only. In general, the extra damage is equal to 30% of your Base Attack.
The bonus has no time limit, and will remain active indefinitely. However, it will immediately dissipate after you make a single Melee attack.
While the BYSSEPS bonus is active, further castings of BYSSEPS will not increase your Attack Bonus any further until it dissipates. However they will still count as successful use, so you will lose Mana and will trigger reaction from the Gods if appropriate.
This bonus is cumulative with other effects that increase Attack Strength by percentage, such as picking up Attack Boost powerups, or racial abilities like that of the Thief or Berserker. In other words, if your bonus for a particular attack would normally be, (for example) 50%, then using BYSSEPS will increase your bonus to 80%. If your original Attack Bonus was negative, BYSSEPS will negate some of it as appropriate. For instance, if the original bonus was -40%, after casting BYSSEPS you will end up with -10%.
The Attack Bonus only applies for Melee attacks, and will not increase the damage done by BURNDAYRAZ. Also, it has no effect on the damage caused by Knockback, which relies solely on your Base Attack Strength. Finally, the bonus applies whether or not your Melee Attacks are Physical in nature, so you can use it even if you have the Magical Attack ability.
BYSSEPS is unlocked from the moment you create a new Profile. It has a certain chance to appear in each dungeon you play, supposedly the same chance as any other unlocked Glyph (though this has yet to be proven conclusively).
BYSSEPS is useful on its own for any character who relies on Melee attacks. It increases the strength of their Melee attack, allowing them to cause more damage than normal for a small amount of Mana.
Depending on the style, you may find it useful to cast the Glyph either once per combat or multiple times.
Characters who rely primarily on Melee Attacks can cast this spell repeatedly - once before each attack if possible. This can potentially increase the total amount of damage they inflict by 30%, if they can afford to cast it for each and every attack. This allows taking out monsters with 30% more Health than you can normally defeat. Alternately, having higher damage means you might need fewer Melee attacks to kill a monster, conserving you the Health you'd have otherwise lost during the last one or more attacks. Melee attackers who rely on prolonged combat will find this especially useful, as they might be able to reduce the number of attacks required to kill a monster by two or even three, given enough Mana!
Characters who use Melee attacks to "finish off" an enemy after a volley of BURNDAYRAZ will also find this useful. It may reduce the number of BURNDAYRAZ required to bring the monster down to a low-enough Health where you can kill it. For instance, if a monster requires two BURNDAYRAZ and a Melee attack to kill, after casting BYSSEPS it may require only one BURNDAYRAZ and a Melee attack. This conserves 3 Mana - not much, but can be significant. This is especially helpful if your Melee attack is also a First Strike, as it will conserve you some Health along with that Mana.
A simple two-Glyph combo. BYSSEPS is used to increase the damage of as many Melee attacks as possible, while leaving enough Mana to cast APHEELSIK on the monster to freeze its Health while you go regenerate. Basically it means you can cause more damage to the monster before you need to Poison it.
This is primarily useful against bosses (or other high-level, high-health monsters), as it can reduce the number of hits you need to kill them by a significant amount. This means conserving Health, which in turn means conserving unexplored dungeon tiles.
As explained above, this combo is mainly used for characters who like to whittle down their opponent to a point where it can be killed by a single attack. BYSSEPS increases the amount of damage you can do with that last hit, meaning that you don't have to cast BURNDAYRAZ as many times to bring the monster to that point. Naturally, this can also be done if you rely on more than one Melee attack to finish off a monster, but this depends mainly on how much Mana you have.
Combine with GETINDARE as a third Glyph to make that last attack a First Strike, enabling you to kill the monster without taking any damage yourself.
For a starting Sorcerer, finding BYSSEPS is a good way to vanquish some tough enemies. Attack monster in Melee combat, then cast BYSSEPS. It will restore 6 Health points thanks to the Sorcerer's natural abilities, and increase your Attack Strength at the same time, allowing you to do more damage with the next attack.
Naturally, by the time you find better spells like BURNDAYRAZ, this tactic is less useful.
BYSSEPS and the Gods
Several Gods in the game have various opinions about the use of BYSSEPS - they may favour it or reject it, depending on their own particular creeds.
As with any other Glyph, Taurog will penalize you -5 Piety points every time you use BYSSEPS. This is unfortunate, as it is a primarily Melee-oriented spell that would otherwise suit the same characters who normally worship Taurog.
Mystera Annur will increase your piety by +1 for every use of BYSSEPS, regardless of whether or not you already had its ability while trying to cast it. Due to its relatively-low cost, you can use it as a quick way to gain Piety with Mystera. However, note that as a worshipper of Mystera your Attack Strength is permanently stuck at 1, meaning the natural effect of the Glyph is completely useless to you.