The applicability of existing Cross-Technology Communication (CTC) methods, which rely on packet-level modulation, is severely limited due to their very low throughput, e.g., tens of bps. Our work, named as WEBee, opens a promising direction for high throughput CTC via physical-level emulation. Specifically, WEBee synthesizes the time-domain signals by choosing appropriate frequency-domain components fed into the subcarriers of WiFi OFDM. WE-Bee can emulate the desired physical-layer ZigBee signals by manipulating only the data bits in WiFi packet payload, requiring neither hardware nor firmware changes in commodity technologies. Moreover, WEBee enables the parallel CTC, where one WiFi frame emulates two ZigBee frames simultaneously. To evaluate the performance, we implemented WEBee on commodity devices (the Atheros AR2425 WiFi card, BCM 4330 WiFi card and CC2420, CC2530 ZigBee devices). Our comprehensive evaluation reveals that WEBee can achieve the CTC between WiFi and ZigBee with a reliable throughput of 126Kbps in noisy environment, 16, 000x faster than current state-of-the-art CTC methods.