headlight buld deformed

I just replaced both low beam headlight bulbs. 98 accord.Both of them had a
strange bubble protrusion from the side of the bulb but were still burning.
What would cause this?

--

 

Last "human"? Not counting aliens here, are you?

 

Every alien I know is allergic to potato chips, so we can count them
out.

 

:^)

 

The bulb installer left oils from their skin on the bulb from touching
it.The oils carbonize from the heat,and then get the quartz glass even
hotter,it creats a hot spot melting the glass.

That is why one should use gloves or a paper towel/cloth to hold the bulb
when installing halogen lamps.

 

The mystery deepens.... Must be a human masquerading as an alien.

Mike

 

Jim is correct, as well as motsco. In high school, many years ago, I was on
stage crew, and if you touched the FOH, (Front of House) lights they bulbed
out. We called it Silzerizing, after a teacher who had a rather large noze.

Dan