Wild chainsaws are not likely to occur in normal games -- it is only in Ao100 that you have a much higher chance of seeing it.
As for the backpack, no, you do not see it wild ever. Come to think of it, has anyone seen a BFG9000 in the wild for Ao100 or any other game modes?
Very rare wild backpacks in Ao100 would be kind of cool.
Why do we keep calling it wild? This isn't Pokemon...
A wild CHAINSAW approaches!
Get 'em, SHOTGUN!
CHAINSAW uses BLOODGOD!
CHAINSAW's DEF rises sharply!
CHAINSAW's ATK rises sharply!
CHAINSAW's SPD rises sharply!
SHOTGUN uses JUGGLER!
Hits 2 times!
CHAINSAW uses RIP!
Critical hit!
SHOTGUN uses ASSEMBLY!
SHOTGUN transforms into ELPHTGUN!
CHAINSAW uses TEAR!
ELPHTGUN uses SHRAPNEL!
It's super effective!
CHAINSAW uses GUTS!
CHAINSAW is storing energy.
Go! Pickup!
(locks in place)
You caught CHAINSAW!
Would you like to give CHAINSAW a nickname?
CHAINSAW -> ZERKSAW
In all seriousness, all pinks (exotics) can be found as a random drop. This includes chainsaws, BFG9000s, nuclear plasma rifles/BFG9000s, assault shotguns, and missile launchers. And possibly anything else I didn't think of. Limes (uniques) are always found randomly, while yellows (artifacts) are never found randomly.
I've actually seen a random chainsaw spawn in a non-A100 game, though when you're not playing a melee run, there isn't much point to it (the zerk effect only activates for the first pickup).
And why isn't there a general 'ask a question, get an answer' thread here?
We had a "quick questions" thread
a while back, feel free to reuse it if you want. It's not stickied, although it may be a good idea to have one anyway.