To dream of a tarantula represents feelings of total hopelessness or despair. You feel powerless to do anything except notice yourself being slowly overtaken by something you fear. Feelings about being slowly trapped by a fear that will consume you.
Alternatively, a tarantula may reflect feelings of fear that you are fully aware of yourself behaving in a way that is slowly readying you for total failure or embarrassment. An irrational fear of the "deadly sin" sloth or that your laziness with important issue will destroy you. Fearing other people's patient confident persistence. Fearing something that is "deadly and slowly coming for you."
Example: A man dreamed of seeing a tarantula. In waking life he was very religious and had been delaying his plans to become a minister believing it was his calling in life. The tarantula may have reflected his irrational fear of watching himself angering God for delaying his ministry and witnessing himself slowly losing his soul for it.
*Please See Spiders