Extract of Dual-Mindedness

This potion can be distilled only from a hormone found in the hypothalamus of a two-headed giant of genius intellect. For 1 minute after drinking this potion, you can concentrate on two spells at the same time, and you have advantage on Constitution saving throws made to maintain your concentration on a spell when you take damage.

Source: Vault of Magic · OGL-1.0a · 5.1