The Emotion Bug causes Base MegaMan's Emotion Window to cycle between Normal, Tired, Angry, and Full Snychro every 60 frames. The bug is only active in Base MegaMan when his Beast Counter is greater than 0. If MegaMan crosses and is later decrossed, the effect will return. MegaMan is still able to receive Angry and Full Synchro normally, but will lose the status when the Emotion bug cycles to the next status. When using 
BugFix, there is a small chance to retain Angry or Full Synchro from Emotion Bug during the time freeze animation.
The chances for each Emotion varies depending on the current emotion MegaMan is in:
| to Normal | to Tired | to Angry | to Full Synchro | |
|---|---|---|---|---|
| from Normal | 14/16 | 1/16 | 1/16 | |
| from Tired | 14/16 | 1/16 | 1/16 | |
| from Angry | 7/16 | 8/16 | 1/16 | |
| from Full Synchro | 7/16 | 8/16 | 1/16 |
Navi Cust parts causing the Bug
Patch Cards causing this bug
Notes
Emotion Bug is the only Bug that can be resolved without BugFix through the use of Beast Out to lower MegaMan's Beast Counter to 0.
Competitive Overview
Emotion Bug provides Base MegaMan the opportunity to deal double damage with any dimming or non-dimming chip that has a damage value at the cost of predictability and potentially being unable to Beast Out during the Custom Screen if MegaMan ends the turn on the Tired Status. Multi-hitting chips will often be used in conjunction with Emotion Bug and damage amplifying chips such as and since the double damage effect is applied after the additive bonus. Depending on a player's luck and patience, this can create some of the highest damaging chip combos in the game.
Because players will want to remain in Base MegaMan to retain the Emotion Bug, it pairs well with other NaviCust parts that require Base MegaMan such as Template:NaviCust, Template:NaviCust, or Template:NaviCust.
Counterplay
Players utilizing the Emotion Bug will want to remain in Base MegaMan, forgoing the benefits of cross utility and damage.
Using can limit your opponents opportunities to execute double damage attacks.
If the opponent ends their turn on either Angry or Full Synchro, you may want to begin your turn defensively to prevent taking a double damage attack.