Alien Symbiote

Notes

The Alien Symbiote is used in the Events step and allows you to use the ability of the chosen staff member twice instead of just once.

If you choose a staff member with an Events step or Park step ability, you can use their ability once and then must wait until it is your turn again to use it a second time - you do get to use the ability twice, but not immediately one after the other.

If you choose a staff member with a Guests step or Cleanup step ability, when there are no turns, you may use the ability immediately two times in total.

You can use the staff member one time, and then activate the symbiote, and then use the staff member a second time. 

If you lose the staff member between activating the symbiote and using the ability, then unfortunately you do indeed lose the benefit.

Thematically, the symbiote is super-charging that staff member to allow them to do twice as much as normal. The symbiote doesn't take on any new abilities itself.