Over the past five years, Valeant Pharmacueticals (BHC 0.60%) stock is up 856%, absolutely smashing the market's returns. And the company has recently made waves by teaming up with activist investor Bill Ackman of Pershing Square to take over Allergan (NYSE: AGN), the specialty pharma company famous for Botox. 

In the following video, Motley Fool analysts Michael Douglass and Brendan Mathews discuss why Allergan's board rejected Valeant's initial offer. As Brendan notes, Allergan's board believes that the company is worth more than Valeant offered. Further, Allergan's board doesn't want to cut its research and development budget, which would certainly happen if they were acquired by Valeant. And the proposed deal includes partial payment in Valeant stock, which Allergan's board argues is overvalued. Despite those concerns, Brendan thinks this deal will get done, though probably at a slightly different price or terms from what was originally proposed.