An investment vehicle - a loan (at some nominal interest rate, but required) that converts into stock in the company when the company does the next Priced Round. This is done to: 1) avoid the legal overhead of a Priced Round and 2) avoid the possibly challenging negotiation over the actual valuation of the company - kicking the valuation can down the road. There may a valuation cap or discount to compensate and incentivize these earlier investors for the additional risk.