If I play my bass with a keyboard amp, will it damage the amp?
Not at all. Synths and keys can pop into bass scales easily because secondary harmonics and low voices. Key amps are pretty much bass amps without a low pass filter to allow dem bright shiny synth noises through, no problems using that config.
Go climb a wall of dicks faggot. This is a refreshing change from /pol/tards and /d/ick gobblers whinging about things they don't like.